Arcadium Lithium (ALTM) 10-Q7 Nov 242024 Q3 Quarterly reportFinancial data

Company Profile

Cover

Cover - shares	9 Months Ended
Cover - shares	Sep. 30, 2024	Nov. 06, 2024
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2024
Document Transition Report	false
Entity File Number	001-38694
Entity Registrant Name	ARCADIUM LITHIUM PLC
Entity Incorporation, State or Country Code	Y9
Entity Tax Identification Number	98-1737136
Entity Address, Address Line One	1818 Market Street
Entity Address, Address Line Two	Suite 2550
Entity Address, City or Town	Philadelphia
Entity Address, State or Province	PA
Entity Address, Country	US
Entity Address, Postal Zip Code	19103
City Area Code	215
Local Phone Number	299-5900
Title of 12(b) Security	Ordinary Shares, par value $1.00 per share
Trading Symbol	ALTM
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		1,075,630,109
Entity Central Index Key	0001977303
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3
Amendment Flag	false
Other Address
Entity Information [Line Items]
Entity Address, Address Line One	Suite 12, Gateway Hub
Entity Address, Address Line Two	Shannon Airport House
Entity Address, City or Town	Shannon, Co. Clare
Entity Address, Country	IE
Entity Address, Postal Zip Code	V14 E370
City Area Code	353-1
Local Phone Number	6875238

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023		Sep. 30, 2024	Sep. 30, 2023
Income Statement [Abstract]
Revenue	$ 203.1	$ 211.4	[1]	$ 718.8	$ 700.7	[1]
Cost of sales	146.9	83.6	[1]	475.8	258.4	[1]
Gross margin	56.2	127.8	[1]	243	442.3	[1]
Impairment charges	51.7	0		51.7	0
Selling, general and administrative expenses	39.7	13.2	[1]	95.1	47.1	[1]
Research and development expenses	1.2	1.3	[1]	3.8	3.3	[1]
Restructuring and other charges	9.7	8.7	[1]	111.4	35	[1]
Total costs and expenses	249.2	106.8	[1]	737.8	343.8	[1]
(Loss)/income from operations before equity in net loss of unconsolidated affiliate, interest expense/(income), net, loss on debt extinguishment and other (gains)/losses	(46.1)	104.6	[1]	(19)	356.9	[1]
Equity in net loss of unconsolidated affiliate	5.9	6.7	[1]	5.9	22	[1],[2]
Interest expense/(income), net	1.5	0	[1]	(18.8)	0	[1]
Loss on debt extinguishment	0	0	[1]	1.1	0	[1],[2]
Other (gains)/losses	(44.8)	1.2	[1]	(202)	(5.3)	[1]
(Loss)/income from operations before income taxes	(8.7)	96.7	[1]	194.8	340.2	[1]
Income tax (benefit)/expense	(33.4)	9.3	[1]	55.7	47.8	[1]
Net income	24.7	87.4	[1],[3],[4]	139.1	292.4	[1],[2],[4]
Net income attributable to noncontrolling interests	8.6	0	[1]	21.7	0	[1]
Net income attributable to Arcadium Lithium plc	$ 16.1	$ 87.4	[1]	$ 117.4	$ 292.4	[1]
Basic earnings per ordinary share (in dollars per share)	$ 0.01	$ 0.20	[1]	$ 0.11	$ 0.68	[1]
Diluted earnings per ordinary share (in dollars per share)	$ 0.01	$ 0.17	[1]	$ 0.10	$ 0.58	[1]
Weighted average ordinary shares outstanding - basic (in shares)	1,075.1	432.4	[1]	1,067.8	432.3	[1]
Weighted average ordinary shares outstanding - diluted (in shares)	1,143.6	503.6	[1]	1,136.4	503.5	[1]

[1] For the three and nine months ended September 30, 2023, basic and diluted earnings per ordinary share and weighted average ordinary shares outstanding - basic and diluted amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Represents the results of predecessor Livent’s operations for three and nine months ended September 30, 2023 which do not include the operations of Allkem. Represents the results of predecessor Livent’s operations for nine months ended September 30, 2023, which do not include the operations of Allkem. Represents the results of predecessor Livent’s operations for three and nine months ended September 30, 2023 and as of December 31, 2023, which do not include the financial position or operations of Allkem. Represents the results of predecessor Livent’s operations for three and nine months ended September 30, 2023, which do not include the operations of Allkem.

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Parenthetical)	Jan. 04, 2024	Sep. 30, 2023
Exchange ratio		2.406
Allkem Livent Merger
Exchange ratio	2.406

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023		Sep. 30, 2024	Sep. 30, 2023
Statement of Comprehensive Income [Abstract]
Net income	$ 24.7	$ 87.4	[1],[2],[3]	$ 139.1	$ 292.4	[1],[3],[4]
Foreign currency adjustments:
Foreign currency translation income/(loss) arising during the period	13.4	(1.8)	[3]	(17.1)	(1.3)	[3]
Total foreign currency translation adjustments	13.4	(1.8)	[3]	(17.1)	(1.3)	[3]
Derivative instruments:
Unrealized hedging (losses)/gains, net of tax of less than zero, $0.2, $(0.1), and zero	(0.1)	(0.6)	[2],[3]	0.2	0	[3]
Reclassification of deferred losses included in net income, net of tax of zero, $(0.1), zero and $(0.1)	0.1	0.2	[2]	0.1	0.2
Total derivative instruments	0	(0.4)	[3]	0.3	0.2	[3]
Other comprehensive income/(loss), net of tax	13.4	(2.2)	[3]	(16.8)	(1.1)	[3]
Comprehensive income	38.1	85.2	[3]	122.3	291.3	[3]
Comprehensive income attributable to noncontrolling interests	11	0	[3]	24.1	0	[3]
Comprehensive income attributable to Arcadium Lithium plc	$ 27.1	$ 85.2	[3]	$ 98.2	$ 291.3	[3]

[1] For the three and nine months ended September 30, 2023, basic and diluted earnings per ordinary share and weighted average ordinary shares outstanding - basic and diluted amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Represents the results of predecessor Livent’s operations for three and nine months ended September 30, 2023 which do not include the operations of Allkem. Represents the results of predecessor Livent’s operations for three and nine months ended September 30, 2023 and as of December 31, 2023, which do not include the financial position or operations of Allkem. Represents the results of predecessor Livent’s operations for three and nine months ended September 30, 2023, which do not include the operations of Allkem. Represents the results of predecessor Livent’s operations for nine months ended September 30, 2023, which do not include the operations of Allkem.

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Statement of Comprehensive Income [Abstract]
Unrealized hedging (losses)/gains, tax	$ 0	$ 200,000	$ (100,000)	$ 0
Reclassification of deferred hedging gain (losses) included in net income, tax	$ 0	$ (100,000)	$ 0	$ (100,000)

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023	[1]
Current assets
Cash and cash equivalents	$ 137.9	$ 237.6
Trade receivables, net of allowance of approximately $0.1 in 2024 and $0.3 in 2023	90.2	106.7
Inventories, net	389.6	217.5
Prepaid and other current assets	247.9	86.4
Total current assets	865.6	648.2
Investments	40	34.8
Property, plant and equipment, net of accumulated depreciation of $345.5 in 2024 and $269.1 in 2023	7,249.2	2,237.1
Goodwill	1,293.2	120.7
Other intangibles, net	64.2	53.4
Deferred income taxes	48.2	1.4
Right of use assets - operating leases, net	54.8	6.8
Other assets	389.4	127.7
Total assets	10,004.6	3,230.1
Current liabilities
Short-term debt and current portion of long-term debt	288.4	2.4
Accounts payable, trade and other	151	115.4
Accrued and other liabilities	175.5	136.8
Contract liability - short-term	55.1	4.4
Operating lease liabilities - current	6.8	1.3
Income taxes	58.5	8.3
Total current liabilities	735.3	268.6
Long-term debt	436	299.6
Operating lease liabilities - long-term	49.7	5.6
Environmental liabilities	7.4	7
Deferred income taxes	1,299.1	126.4
Contract liability - long-term	251.2	217.8
Other long-term liabilities	92	21.3
Commitments and contingent liabilities (Note 20)	0	0
Total current and long-term liabilities	2,870.7	946.3
Equity
Ordinary shares; $1.00 par value; 5,000,000,000 shares authorized; 1,075,427,002 and 433,059,946 shares issued; 1,075,164,487 and 432,796,277 outstanding as of September 30, 2024 and December 31, 2023, respectively	0.1	0.1
Capital in excess of par value of ordinary shares	5,581.7	1,170.4
Retained earnings	781.9	664.5
Accumulated other comprehensive loss	(66.6)	(49.8)
Treasury shares, ordinary, at cost; 262,515 and 263,669 shares as of September 30, 2024 and December 31, 2023, respectively	(1)	(1)
Total Arcadium Lithium plc shareholders’ equity	6,296.1	1,784.2
Noncontrolling interests	837.8	499.6
Total equity	7,133.9	2,283.8
Total liabilities and equity	$ 10,004.6	$ 3,230.1

[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Current assets
Allowance for trade receivables	$ 0.1	$ 0.3
Accumulated depreciation	$ 345.5	$ 269.1
Equity
Ordinary shares par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	5,000,000,000	5,000,000,000
Common stock, shares issued (in shares)	1,075,427,002	433,059,946
Common stock, outstanding (in shares)	1,075,164,487	432,796,277
Treasury stock, shares (in shares)	262,515	263,669

CONDENSED CONSOLIDATED STATEM_5

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2024	Sep. 30, 2023
Cash (used in)/provided by operating activities:
Net income		$ 139.1	$ 292.4	[1],[2],[3]
Adjustments to reconcile net income to cash (used in)/provided by operating activities:
Depreciation and amortization		77.4	21.5	[2]
Restructuring and other charges		(50.6)	22.5	[2]
Impairment charges		51.7	0
Deferred income taxes		(152.9)	(4.8)	[2]
Share-based compensation		9.1	6.2	[2]
Change in investments in trust fund securities		(1.2)	(0.2)	[2]
Loss on debt extinguishment		1.1	0	[1],[2]
Equity in net loss of unconsolidated affiliate		5.9	22	[1],[2]
Other gain, Blue Chip Swap		(64.9)	(21.4)	[2]
Other non-cash adjustments		0.3	(0.3)	[2]
Changes in operating assets and liabilities:
Trade receivables, net		83.3	29.9	[2]
Inventories		(48.1)	(56.2)	[2]
Accounts payable, trade and other		(146.7)	(33.6)	[2]
Changes in deferred compensation		2.1	1.2	[2]
Contract liability - short-term		50.7	(5.8)	[2]
Contract liability - long-term		(22)	0	[2]
Income taxes		(27.7)	(11.6)	[2]
Change in prepaid and other current assets and other assets		(97.4)	4.9	[2]
Change in accrued and other current liabilities and other long-term liabilities		31.9	(4.9)	[2]
Cash (used in)/provided by operating activities		(158.9)	261.8	[2]
Cash used in investing activities:
Capital expenditures	[4]	(778.7)	(239.4)	[2]
Proceeds from Blue Chip Swap, net of purchases		64.9	21.4	[2]
Acquired cash & cash equivalents - Allkem Livent Merger		681.4	0	[2]
Investment in-transit - Nemaska Lithium		(43.9)	0
Investments in unconsolidated affiliates	[5]	(40.7)	(85.4)	[2]
Other investing activities		(12.8)	(12.1)	[2]
Cash used in investing activities		(129.8)	(315.5)	[2]
Cash provided by/(used in) financing activities:
Proceeds from Revolving Credit Facility		222	0	[2]
Repayments of Revolving Credit Facility		(123)	0	[2]
Repayments of project loan facilities		(83.2)	0	[2]
Proceeds from prepayment of customer supply agreement		150	0	[2]
Capital contribution from noncontrolling interest - Nemaska Lithium		39.1	0	[2]
Payment of deposit to customs authorities		0	(21.7)	[2]
Other financing activities		(1.8)	0.2	[2]
Cash provided by/(used in) financing activities		203.1	(21.5)	[2]
Effect of exchange rate changes on cash and cash equivalents		(14.1)	(1.2)	[2]
Decrease in cash and cash equivalents		(99.7)	(76.4)	[2]
Cash and cash equivalents, beginning of period		237.6	189	[2]
Cash and cash equivalents, end of period		137.9	112.6	[2]
Supplemental Disclosure for Cash Flow:
Cash payments for income taxes, net of refunds		136	55.3	[6]
Cash payments for interest	[4]	25.1	11.3	[6]
Cash payments for Restructuring and other charges		162	12.2	[6]
Accrued capital expenditures		166.5	39.5	[6]
Operating lease right-of-use assets and lease liabilities recorded for ASC 842		$ 1	$ 0.9	[6]

[1] For the three and nine months ended September 30, 2023, basic and diluted earnings per ordinary share and weighted average ordinary shares outstanding - basic and diluted amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Represents the results of predecessor Livent’s operations for three and nine months ended September 30, 2023 which do not include the operations of Allkem. Represents the results of predecessor Livent’s operations for nine months ended September 30, 2023, which do not include the operations of Allkem. Represents the results of predecessor Livent’s operations for three and nine months ended September 30, 2023, which do not include the operations of Allkem. For the nine months ended September 30, 2024 and 2023, $17.1 million and $12.6 million of interest expense was capitalized, respectively. For the nine months ended September 30, 2024 and 2023 cash payments for interest capitalized were $16.6 million and $11.3 million, respectively. 3. Represents the Company's cash contributed to Nemaska Lithium in the third quarter of 2024 which, due to one-quarter lag reporting, is not yet recorded in our consolidation of Nemaska. The balance is recorded to Other assets - noncurrent because the cash is expected to be used by Nemaska primarily for capital expenditures. See Note 9 for details. On October 18, 2023 we began consolidating Nemaska Lithium, see Note 9 for details. Represents the results of predecessor Livent’s operations for nine months ended September 30, 2023, which do not include the operations of Allkem.

CONDENSED CONSOLIDATED STATEM_6

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Statement of Cash Flows [Abstract]
Interest expense capitalized	$ 17.1	$ 12.6
Interest paid, capitalized	$ 16.6	$ 11.3

CONDENSED CONSOLIDATED STATEM_7

CONDENSED CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Millions		Total		Ordinary Shares, $1.00 Per Share Par Value	Capital In Excess of Par	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Shares	Non-controlling Interest
Beginning balance at Dec. 31, 2022	[1]	$ 1,443		$ 0.1	$ 1,160.4	$ 334.4	$ (51)	$ (0.9)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	[1]	114.8				114.8
Share compensation plans	[1]	1.9			1.9
Shares withheld for taxes and option costs - ordinary share issuances	[1]	(0.5)			(0.5)
Exercise of stock options	[1]	0.1			0.1
Net hedging gains, net of income tax	[1]	0.2					0.2
Foreign currency translation adjustments	[1]	1.5					1.5
Ending balance at Mar. 31, 2023	[1]	1,561		0.1	1,161.9	449.2	(49.3)	(0.9)	0
Beginning balance at Dec. 31, 2022	[1]	1,443		0.1	1,160.4	334.4	(51)	(0.9)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	[2],[3],[4]	292.4
Net hedging gains, net of income tax	[4]	0
Reclassification of deferred hedging losses, net of tax		0.2
Ending balance at Sep. 30, 2023	[1]	1,740.6		0.1	1,166.7	626.8	(52.1)	(0.9)	0
Beginning balance at Mar. 31, 2023	[1]	1,561		0.1	1,161.9	449.2	(49.3)	(0.9)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	[1]	90.2				90.2
Share compensation plans	[1]	2.1			2.1
Exercise of stock options	[1]	0.3			0.3
Net hedging gains, net of income tax	[1]	0.4					0.4
Foreign currency translation adjustments	[1]	(1)					(1)
Ending balance at Jun. 30, 2023	[1]	1,653		0.1	1,164.3	539.4	(49.9)	(0.9)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	[1]	87.4	[2],[4]			87.4
Share compensation plans	[1]	2.2			2.2
Exercise of stock options	[1]	0.2			0.2
Net hedging gains, net of income tax	[1]	(0.6)	[4]				(0.6)
Reclassification of deferred hedging losses, net of tax	[1]	0.2					0.2
Foreign currency translation adjustments	[1]	(1.8)					(1.8)
Ending balance at Sep. 30, 2023	[1]	1,740.6		0.1	1,166.7	626.8	(52.1)	(0.9)	0
Beginning balance at Dec. 31, 2023		2,283.8	[5]	0.1	1,170.4	664.5	(49.8)	(1)	499.6
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		19.9				15.6			4.3
Allkem Livent Merger		4,665.4			4,390.4				275
Share compensation plans		15.8			15.8
Shares withheld for taxes and option costs - ordinary share issuances		(2.6)			(2.6)
Net hedging gains, net of income tax		0.2					0.2
Foreign currency translation adjustments		(20.2)					(20.2)
Ending balance at Mar. 31, 2024		6,962.3		0.1	5,574	680.1	(69.8)	(1)	778.9
Beginning balance at Dec. 31, 2023		2,283.8	[5]	0.1	1,170.4	664.5	(49.8)	(1)	499.6
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		139.1
Net hedging gains, net of income tax		0.2
Reclassification of deferred hedging losses, net of tax		0.1
Ending balance at Sep. 30, 2024		7,133.9		0.1	5,581.7	781.9	(66.6)	(1)	837.8
Beginning balance at Mar. 31, 2024		6,962.3		0.1	5,574	680.1	(69.8)	(1)	778.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		94.5				85.7			8.8
Capital contribution from noncontrolling interest		39.1							39.1
Share compensation plans		3.9			3.9
Net hedging gains, net of income tax		0.1					0.1
Foreign currency translation adjustments		(10.3)					(10.3)
Ending balance at Jun. 30, 2024		7,089.6		0.1	5,577.9	765.8	(80)	(1)	826.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		24.7				16.1			8.6
Share compensation plans		3.8			3.8
Net hedging gains, net of income tax		(0.1)					(0.1)
Reclassification of deferred hedging losses, net of tax		0.1					0.1
Foreign currency translation adjustments		15.8					13.4		2.4
Ending balance at Sep. 30, 2024		$ 7,133.9		$ 0.1	$ 5,581.7	$ 781.9	$ (66.6)	$ (1)	$ 837.8

[1] Represents the results of predecessor Livent’s operations for three and nine months ended September 30, 2023 and as of December 31, 2023, which do not include the financial position or operations of Allkem. For the three and nine months ended September 30, 2023, basic and diluted earnings per ordinary share and weighted average ordinary shares outstanding - basic and diluted amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Represents the results of predecessor Livent’s operations for three and nine months ended September 30, 2023 which do not include the operations of Allkem. Represents the results of predecessor Livent’s operations for nine months ended September 30, 2023, which do not include the operations of Allkem. Represents the results of predecessor Livent’s operations for three and nine months ended September 30, 2023, which do not include the operations of Allkem. Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

CONDENSED CONSOLIDATED STATEM_8

CONDENSED CONSOLIDATED STATEMENTS OF EQUITY (Parenthetical) - $ / shares	Sep. 30, 2024	Jan. 04, 2024	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022
Statement of Stockholders' Equity [Abstract]
Ordinary shares par value (in dollars per share)	$ 1	$ 1	$ 1	$ 1	$ 1

Description of the Business

Description of the Business	9 Months Ended
Description of the Business	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of the Business	Description of the Business Background and Nature of Operations Arcadium Lithium plc ("Arcadium", "Arcadium Lithium", "we", "us", "Company" or "our") is a public limited company incorporated under the laws of the Bailiwick of Jersey. On January 4, 2024, Arcadium Lithium completed the previously announced Allkem Livent Merger by which Livent Corporation, a Delaware corporation ("Livent"), and Allkem Limited, an Australian company limited by shares ("Allkem"), became wholly owned subsidiaries of Arcadium Lithium. On January 4, 2024, the Company's shares started trading on the New York Stock Exchange under the trading symbol ALTM. See Note 4, Allkem Livent Merger for further details. While Arcadium Lithium is a newly formed company from the merger of Allkem and Livent, our company has a rich heritage of innovation and a long, proven history of producing performance lithium compounds in a safe and sustainable manner. We are vertically integrated, with a global footprint and industry-leading end-to-end capabilities across lithium production including hard-rock mining, conventional pond-based brine extraction, direct lithium brine extraction and lithium chemicals manufacturing. Our lithium asset portfolio, consisting of both operating assets and development projects, provides us with global reach, scale, and product flexibility. Today we have operating resources in Argentina and Australia and downstream conversion assets in the U.S., China, Japan, and the U.K. We also have multiple development stage projects in Argentina (greenfield and brownfield) and Canada (greenfield) that will in time allow us to increase production capabilities and meet the future needs of customers around the world. In the U.S., we operate the only integrated mine-to-metal production facility in the Western Hemisphere for high purity lithium metal, a core component of next generation battery technologies. We manufacture a wide range of lithium products, including battery-grade lithium hydroxide, battery-grade lithium carbonate, spodumene, and other specialty chemicals such as butyllithium and high purity lithium metal. Our products are used in various performance applications, including lithium-based batteries, specialty polymers and pharmaceutical products and chemical synthesis applications. Pending Rio Tinto Transaction On October 9, 2024, Arcadium Lithium entered into the Transaction Agreement (the "Rio Tinto Transaction Agreement") with Rio Tinto Western Holdings Limited, a private limited company incorporated under the laws of England & Wales ("Parent"), and Rio Tinto BM Subsidiary Limited, a private limited company incorporated under the laws of England & Wales ("Buyer"). The Rio Tinto Transaction Agreement provides that pursuant to a scheme of arrangement (the "Scheme") under the Companies (Jersey) Law 1991, at the effective time of the Scheme, all of the ordinary shares, par value $1.00 per share, of the Company (the "Company Shares"), including the Company Shares represented by CHESS depositary interests issued by the Company and listed on the securities exchange operated by ASX Limited, then outstanding will be transferred from the shareholders of the Company to Buyer (or an affiliate of Buyer) in exchange for the right to receive an amount in cash, without interest, equal to $5.85 per Company Share (the "Rio Tinto Transaction"). If the Rio Tinto Transaction is consummated, the Company’s ordinary shares will be delisted from the New York Stock Exchange and the Company’s registration under the Exchange Act of 1934, as amended, will be terminated as promptly as practicable after the effective time of the Rio Tinto Transaction, and the quotation on the Australian Securities Exchange Ltd of the CHESS depositary interests issued by the Company will be suspended immediately prior to the effective time of the Rio Tinto Transaction. The closing of the Rio Tinto Transaction is subject to customary closing conditions under the Rio Tinto Transaction Agreement, including, among others: the approval of the Scheme by the Company’s shareholders; all applicable governmental consents under specified antitrust and investment screening laws having been obtained and remaining in full force and effect and all applicable waiting periods having expired, lapsed or been terminated (as applicable); no governmental entity of a competent jurisdiction having issued any order that is in effect and restrains, enjoins or otherwise prohibits the consummation of the Rio Tinto Transaction and no governmental entity having jurisdiction over any party having adopted any law that is in effect and makes consummation of the Rio Tinto Transaction illegal or otherwise prohibited; the representations and warranties of each of the Company and Parent being true and correct to the extent required by, and subject to the applicable materiality standards set forth in, the Rio Tinto Transaction Agreement; each of the Company, Parent and Buyer having in all material respects performed the obligations and complied with the covenants required to be performed or complied with by it under the Rio Tinto Transaction Agreement; and there having been no material adverse effect (as defined in the Rio Tinto Transaction Agreement). The timing surrounding whether these conditions will be satisfied or waived, if at all, is uncertain. Additionally, other events could intervene to delay or result in the failure to close the Rio Tinto Transaction. The Rio Tinto Transaction is currently expected to close in mid-2025, subject to satisfaction of the closing conditions. If the Rio Tinto Transaction has not closed by October 9, 2025 (subject to extension until April 9, 2026 in order to obtain antitrust or investment screening law or other regulatory approvals), either the Company or Parent may choose to terminate the Rio Tinto Transaction Agreement. The Rio Tinto Transaction Agreement provides that, if the Rio Tinto Transaction Agreement is terminated, the Company will pay a $200 million termination fee to Rio Tinto in the case of certain events described in the Rio Tinto Transaction Agreement, including if the Company terminates the Rio Tinto Transaction Agreement in connection with the Board of Directors of the Company changing its recommendation and if Rio Tinto terminates the Rio Tinto Transaction Agreement due to the Board of Directors of the Company changing its recommendation. The termination fee may also become payable by the Company if the Rio Tinto Transaction Agreement is terminated in certain circumstances and the Company enters into an agreement for an alternative transaction within twelve months of such termination. However, this right to terminate the Rio Tinto Transaction Agreement will not be available to the Company or Parent if such party has materially breached the Rio Tinto Transaction Agreement and the breach is the principal cause of the failure of the closing to have occurred prior to such date. The Company or Parent may elect to terminate the Rio Tinto Transaction Agreement in certain other circumstances, including if the Company’s shareholders fail to approve the Rio Tinto Transaction at the shareholder meetings, and the Company and Parent can mutually decide to terminate the Rio Tinto Transaction Agreement at any time prior to the closing, before or after the required approval by the Company’s shareholders. The foregoing summary of the Rio Tinto Transaction Agreement and the Rio Tinto Transaction contemplated thereby does not purport to be complete and is qualified in its entirety by reference to the terms and conditions of the Rio Tinto Transaction Agreement, a copy of which is filed as Exhibit 2.1 to this Form 10-Q.

Significant Accounting Policies

Significant Accounting Policies and Related Financial Information	9 Months Ended
	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Significant Accounting Policies and Related Financial Information	Significant Accounting Policies and Related Financial Information In this Form 10-Q, the results of the Company as of September 30, 2024 and for the three and nine months ended September 30, 2024 include the operations and financial position of Allkem, respectively. Because Arcadium Lithium plc is the successor company to Livent in the Allkem Livent Merger, we are presenting the results of predecessor Livent’s operations for the three and nine months ended September 30, 2023 and as of December 31, 2023, which do not include the financial position or operations of Allkem. Refer to Note 4 for further information related to the Allkem Livent Merger. The accompanying condensed consolidated financial statements were prepared in accordance with the requirements of the Securities and Exchange Commission ("SEC") for interim reporting. As permitted under those rules, certain notes or other financial information that are normally required by U.S. GAAP have been condensed or omitted from these interim financial statements. The financial statements included in this report reflect all normal and recurring adjustments which, in the opinion of management, are necessary for a fair presentation of our condensed consolidated balance sheets as of September 30, 2024 and December 31, 2023, the condensed consolidated results of operations, the condensed consolidated statement of comprehensive income and the condensed consolidated statement of changes in equity for the three and nine months ended September 30, 2024 and 2023, and the condensed consolidated cash flows for the nine months ended September 30, 2024 and 2023. All intercompany transactions and balances have been eliminated in consolidation. For entities that we control, but own less than 100%, we record the minority ownership as noncontrolling interest. The unaudited results of operations for the interim periods reported are not necessarily indicative of results to be expected for the full year. These statements, therefore, should be read in conjunction with the annual consolidated financial statements and related notes included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2023 (the "2023 Annual Report on Form 10-K"). Reclassifications Certain prior period balances have been reclassified to conform to the current period presentation in the condensed consolidated financial statements and the accompanying notes. Effective April 1, 2024, we began presenting gains and losses from foreign currency remeasurements as a component of Other gains/losses. Prior to April 1, 2024, we included gains and losses resulting from foreign currency remeasurements as a component of Cost of sales and Restructuring and other charges in the condensed consolidated statement of operations. The following tables summarize the accounts that were recast for the three and nine months ended September 30, 2023 and the three months ended March 31, 2024 to conform to the current period presentation. Three Months Ended September 30, Nine Months Ended September 30, 2023 2023 (in Millions) Prior Presentation Loss/(gain) Reclassified Recast Presentation Prior Presentation Loss/(gain) Reclassified Recast Presentation Cost of sales $ 94.9 $ 11.3 $ 83.6 $ 274.8 $ 16.4 $ 258.4 Restructuring and other charges 8.6 (0.1) 8.7 34.7 (0.3) 35.0 Other (gains)/losses (10.0) 11.2 1.2 (21.4) 16.1 (5.3) Three Months Ended March 31, 2024 (in Millions) Prior Presentation (Gain)/loss Reclassified Recast Presentation Cost of sales $ 116.8 $ (38.0) $ 154.8 Restructuring and other charges 83.6 3.8 79.8 Other (gains)/losses (43.1) (34.2) (77.3) Segment Information In January 2024, Arcadium Lithium completed the Allkem Livent Merger. See Note 4, Allkem Livent Merger for further details. Following the closing of the Allkem Livent Merger, we currently operate as one reportable segment based on the commonalities among our products and services. As integration evolves, we will continue to assess this determination. Revenue Recognition Revenue from product sales is recognized when we satisfy a performance obligation by transferring the promised goods to a customer, that is, when control of the good transfers to the customer. Payment terms generally range from 20 to 180 days. In determining when the control of goods is transferred, we typically assess, among other things, the transfer of title and risk of loss and the shipping terms of the contract. We record amounts billed for shipping and handling fees as revenue. Costs incurred for shipping and handling are recorded in cost of sales. When we perform shipping and handling activities after the transfer of control to the customer (e.g., when control transfers prior to delivery), they are considered fulfillment activities, and accordingly, the costs are accrued to cost of sales when the related revenue is recognized. Amounts billed for sales and use taxes, VAT, and certain excise and other specific transactional taxes imposed on revenue-producing transactions are presented on a net basis and excluded from revenue in the condensed consolidated statements of operations. We record a liability until remitted to the respective taxing authority. We satisfy our obligations by transferring goods and services in exchange for consideration from customers. The timing of performance sometimes differs from the timing the associated consideration is received from the customer, thus resulting in the recognition of a contract asset or liability. These may arise from provisional pricing within certain of our customer contracts, or if the customer’s payment of consideration is received prior to completion of our related performance obligation. Provisional pricing results in variable consideration which we estimate by using an expected value method taking into account all information that is reasonably available including publicly available pricing forecasts. We only include variable consideration within the transaction price to the extent that it is probable that a significant reversal in the amount of revenue recognized will not occur. Equity method investments We stop applying the equity method when we have reduced the value of our equity method investment, commitments and additional investments (i.e., loans or advances) in the investee to zero. If the investee subsequently reports net income, we resume applying the equity method when our share of that net income is equal to the suspended losses (i.e., our share of the investee's net losses not previously recognized). If facts and circumstances indicate that a decrease in value of the investment has occurred that is other than temporary, we recognize an impairment loss equal to an amount by which the carrying amount exceeds the fair value of the equity method investment. There were no impairments during the nine months ended September 30, 2024. Goodwill The Company accounts for goodwill and other intangibles acquired in a business combination in conformity with current accounting guidance that requires that goodwill and indefinite-lived intangible assets not be amortized. Under the guidance, goodwill is tested for impairment by comparing the estimated fair value of reporting units to the related carrying value. Reporting units are either operating business segments or one level below operating business segments for which discrete financial information is available and for which operating results are regularly reviewed by the business management. In applying the goodwill impairment test, a qualitative test ("Step 0") is initially performed, under which qualitative factors are assessed to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying value. Qualitative factors may include, but are not limited to, economic conditions, industry and market considerations, cost factors, overall financial performance of the reporting units and other entity and reporting unit specific events. If after assessing these qualitative factors, it is determined that it is "more-likely-than-not" that the fair value of the reporting unit is less than the carrying value, a quantitative test ("Step 1") is performed. During Step 1, the fair value is estimated using a discounted cash flow model. Impairment evaluations of goodwill could result in a reduction in our recorded asset values which could have a material adverse effect on our financial position and results of operations. We perform reviews of goodwill on an annual basis, or more frequently if triggering events indicate a possible impairment. We test goodwill at the reporting unit level by comparing the carrying value of the net assets of the reporting unit, including goodwill, to the reporting unit's fair value. If the carrying values of goodwill exceed their fair value, the goodwill would be considered impaired. If any impairment or related charge is warranted, our financial position and results of operations could be materially affected. Any such impairment or related charge could be a result of, for example, sustained declines in the Company’s stock price; the deterioration of the cost of equity or debt capital increases due to valuations for comparable companies or comparable acquisitions valuations; or the deterioration of the outlook for future cash flows for the reporting unit due to but not limited to, increased competition, changes to discount rate, downward forecast revisions, restricted plans or changes in applicable regulations affecting our business. Mine Development Costs Mine development costs include: a) exploration and evaluation ("E&E") expenditures incurred during the search for mineral resources as well as the determination of the technical feasibility and commercial viability of extracting the mineral resource; and b) stripping costs of removing overburden and waste materials to access the mineral body at an open pit mine. The Company capitalizes E&E expenditures to Property, Pland and Equipment ("PP&E") under a successful efforts basis when proven and probable reserves are established for the sites where E&E activities are being performed. E&E assets recognized as part of business combinations are also capitalized. All other E&E expenditures are expensed. Stripping costs incurred prior to the production phase are capitalized to PP&E during the development of an open pit mine. When multiple open pits exist at a mining complex utilizing common processing facilities, such pre-production stripping costs are capitalized at each pit. The removal, production, and sale of de minimis saleable materials may occur during the development phase of an open pit mine and are assigned incremental mining costs related to the removal of that material. The production phase of an open pit mine commences when saleable minerals, beyond a de minimis amount, are produced. Stripping costs incurred during the production phase of a mine are variable production costs that are included as a component of inventory to be recognized in Cost of sales in the same period as the revenue from sale of that inventory. Capitalized mine development costs are amortized using the units-of-production method based on estimated recoverable minerals in proven and probable reserves, and are amortized over the estimated life of the mineral body. Mineral Interests Mineral interests include acquired interests in production, development and exploration stage properties. Mineral interests are capitalized at their fair value at the acquisition date, either as an individual asset purchase or as part of a business combination. Mineral interests in the development and exploration stage are not amortized until the underlying property is converted to the production stage, at which point the mineral interests are amortized over the estimated recoverable proven and probable reserves using a units-of-production method. Asset Retirement Obligations The Company accounts for asset retirement obligations ("AROs") in accordance with ASC 410-20, Asset Retirement Obligations "ASC 410-20". We record AROs at present value at the time the liability is incurred if we can reasonably estimate the settlement date. The associated AROs are capitalized as part of the carrying amount of related long-lived assets. In future periods, the liability is accreted to its present value and the capitalized cost is depreciated over the useful life of the related asset. We also adjust the liability for changes resulting from the passage of time and/or revisions to the timing or the amount of the original estimate. Upon retirement of the long-lived asset, we settle the obligation for its recorded amount. See Note 14, for details. The carrying amounts of the AROs as of September 30, 2024 and December 31, 2023 was $12.5 million and $3.7 million, respectively. These amounts are included in Accrued and other current liabilities and Other long-term liabilities in our condensed consolidated balance sheets. Blue Chip Swap Our wholly owned subsidiaries in Argentina use the U.S. dollar as their functional currency. Argentina peso-denominated monetary assets and liabilities are remeasured at each balance sheet date to the official currency exchange rate then in effect which represents the exchange rate available for external commerce (import payments and export collections) and financial payments, with currency remeasurement and other transaction gains and losses recognized in earnings. In September 2019, the President of Argentina reinstituted exchange controls restricting foreign currency purchases in an attempt to stabilize Argentina’s financial markets. As a result, a legal trading mechanism known as the Blue Chip Swap emerged in Argentina for all individuals or entities to transfer U.S. dollars out of and into Argentina. The Blue Chip Swap rate is the implicit exchange rate resulting from the Blue Chip Swap transaction. In the first half of 2024, U.S. dollars were transferred into Argentina through the Blue Chip Swap method whereby we realized a gain from the purchase in U.S. dollars and sale in Argentina pesos of Argentina Sovereign U.S. dollar-denominated bonds. The gain of $14.4 million and $64.9 million for the three and nine months ended September 30, 2024 was recorded to Other (gains)/losses in our condensed consolidated statements of operations. Li-Metal transaction On August 2, 2024, Arcadium announced it acquired the lithium metal division of Li-Metal Corp. The all-cash $11 million USD transaction includes the intellectual property and physical assets related to lithium metal production, including a pilot production facility in Ontario, Canada.

Recently Issued and Adopted Acc

Recently Issued and Adopted Accounting Pronouncements and Regulatory Items	9 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
Recently Issued and Adopted Accounting Pronouncements and Regulatory Items	Recently Issued and Adopted Accounting Pronouncements and Regulatory Items In December 2023, the Financial Accounting Standard Board ("FASB") issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures . This ASU enhances existing income tax disclosures to better assess how an entity's operation and related tax risks, tax planning, and operational opportunities affect its tax rate and prospects for future cash flows. The ASU is effective for annual periods beginning after December 15, 2024. We are currently evaluating the effect the guidance will have on our condensed consolidated financial statements. In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures . This ASU improves reportable segment disclosure requirements, primarily through enhanced disclosures related to significant segment expenses. The ASU is effective for annual periods beginning after December 15, 2023, and interim periods beginning after December 15, 2024. We are currently evaluating the effect the guidance will have on our condensed consolidated financial statements.

Allkem Livent Merger

Allkem Livent Merger	9 Months Ended
Allkem Livent Merger	Sep. 30, 2024
Business Combination, Asset Acquisition, and Joint Venture Formation [Abstract]
Allkem Livent Merger	Allkem Livent Merger On January 4, 2024 (the "Acquisition Date") Arcadium completed the previously announced Allkem Livent Merger by and among Livent Corporation, a Delaware corporation ("Livent"), Allkem Limited, an Australian public company ("Allkem"), Arcadium Lithium plc, a public limited company incorporated under the laws of the Bailiwick of Jersey ("Arcadium"), Lightning-A Merger Sub, Inc. ("Merger Sub"), and Arcadium Lithium Intermediate IRL Limited, a private company limited by shares and incorporated and registered in Ireland ("Irish IntermediateCo"). The transaction was consummated by way of (a) a scheme of arrangement under Australian law, pursuant to which each issued, fully paid ordinary share of Allkem held by Allkem shareholders was exchanged for either one Arcadium Lithium CHESS Depositary Instrument (a "CDI") quoted on the Australian Stock Exchange (each CDI representing a beneficial ownership interest in one Arcadium ordinary share), or one Arcadium ordinary share (par value $1.00 per share) and (b) a merger, whereby Merger Sub, a wholly owned subsidiary of Irish IntermediateCo (a direct wholly owned subsidiary of Arcadium) merged with and into Livent, with Livent as the surviving entity. Each share of Livent common stock, par value $0.001 per share (each, a "Livent Share"), was converted into the right to receive 2.406 Arcadium ordinary shares. Pursuant to the Allkem Livent Merger, 433,156,855 Arcadium ordinary shares (including 96,909 related to accelerated PRSU awards) were issued to former Livent stockholders and 641,337,840 Arcadium ordinary shares (comprising 98,725,616 Arcadium ordinary shares and 542,612,224 CDIs in respect of Arcadium ordinary shares) were issued to former Allkem shareholders. The Acquisition Date fair value of consideration transferred consisted of the following: (in millions) Amount Consideration: Fair value of Arcadium ordinary shares issued to Allkem shareholders $ 4,385.6 Fair value of converted Allkem performance rights attributable to pre-combination service 4.8 Total consideration $ 4,390.4 The Allkem Livent Merger meets the criteria to be accounted for as a business combination and is accounted for using the acquisition method of accounting with Livent being treated as the accounting acquirer. Under the acquisition method of accounting, the assets and liabilities of Allkem and its subsidiaries are recorded at their respective fair values as of the date of completion of the Allkem Livent Merger and the difference between the fair value of the consideration paid for the acquired entity and fair value of the net assets acquired is recorded as goodwill. The fair value of the assets, liabilities and noncontrolling interest of Allkem under the business combination guidance, including the impact of income taxes, is preliminary. The preliminary fair value allocation is subject to change for up to one year subsequent to the Acquisition Date. Determining the fair value of the assets and liabilities of Allkem requires judgement and certain assumptions to be made, the most significant of these being related to the valuation of Allkem's mining properties and rights. During the nine months ended September 30, 2024, adjustments were made within the permitted measurement period for the following: an increase to property, plant and equipment of $0.6 million, decrease to deferred income tax assets of $16.7 million, increase to accounts payable trade and other of $1.8 million, decrease to income taxes of $0.3 million, decrease to environmental liabilities of $9.1 million, decrease to deferred income tax liabilities of $27.7 million, increase to other long term liabilities of $3.7 million, and a net decrease in goodwill of $15.3 million. The measurement period adjustments have been reflected as current period adjustments in the nine months ended September 30, 2024, in accordance with the guidance in ASU 2015-16 “Business Combinations.” The measurement period adjustments had no effect on earnings or cash in the current period. Transaction and related costs directly attributable to the acquisition of Allkem, consisting primarily of advisor fees, legal fees, accounting fees, and certain deal related bonuses were $12.2 million and $99.0 million, for the three and nine months ended September 30, 2024, respectively. The costs were expensed as incurred and are included in restructuring and other charges. The following table summarizes the preliminary purchase price allocation for the Allkem Livent Merger as of January 4, 2024, which is subject to change: (in Millions, except per share amounts) Amount Total consideration $ 4,390.4 Assets acquired: Cash and cash equivalents $ 681.4 Trade receivables 64.2 Inventories 121.3 Prepaid and other current assets 87.2 Property, plant and equipment 4,326.1 Right of use assets - operating leases, net 53.4 Deferred income tax assets 9.6 Other assets (1) 192.7 Total assets acquired $ 5,535.9 Liabilities assumed: Accounts payable, trade and other $ 223.7 Accrued and other current liabilities 35.1 Income taxes 78.5 Long-term debt including current portion 301.7 Operating lease liabilities - long-term 53.4 Environmental liabilities 9.8 Deferred income tax liabilities 1,289.0 Other long-term liabilities 53.2 Total liabilities assumed $ 2,044.4 Fair value of net assets acquired $ 3,491.5 Add: Fair value of noncontrolling interests acquired 275.0 Fair value of net assets acquired less noncontrolling interests acquired $ 3,216.5 Goodwill $ 1,173.9 ___________________ 1. Includes long-term semi-finished goods inventory. Trade receivables The $64.2 million of acquired trade receivables represents the fair value of the gross amount due under the contracts. Property, Plant and Equipment Property, plant and equipment is inclusive of the fair value of mineral rights totaling $2,745.0 million and non-mineral rights property, plant and equipment totaling $1,581.1 million. The fair value of the mineral rights was estimated using the multi-period excess earnings method. The excess earnings methodology is an income approach methodology that estimates the projected cash flows of the business attributable to the asset, net of charges for the use of other identifiable assets of the business including working capital, fixed assets, and other intangible assets. Mineral rights are depreciated using a units-of-production method while all other property, plant and equipment is depreciated using the straight-line method. Goodwill Goodwill from acquisitions represents the excess of the purchase price over the fair value of net assets acquired. The amount disclosed within the table, subject to change for up to one year subsequent to the Acquisition Date, is attributable to the value of growth opportunities and expected synergies created by incorporating Allkem's business and operations into the Company's operations and the value of the assembled workforce. The goodwill has no amortizable basis for income tax purposes. Allkem revenues and earnings The following table represents Allkem's revenues and net earnings included in Arcadium's condensed consolidated statements of operations from the Acquisition Date through September 30, 2024. (in Millions) Three Months Ended September 30, Nine Months Ended September 30, 2024 Revenue $ 56.6 $ 242.9 (Loss)/income from operations before income taxes $ (44.6) $ 107.6 Pro Forma Financial Information Due to the Allkem Livent Merger closing on January 4, 2024, all activity in the first quarter of 2024 except for the first three days of January, which management deemed not material, is included in Arcadium’s condensed consolidated statements of operations. The following unaudited pro forma financial information for the three and nine months ended September 30, 2023 is based on our historical consolidated financial statements adjusted to reflect the Allkem Livent Merger as if it occurred on January 1, 2023, the first day of the most recently completed fiscal year. The unaudited pro forma financial information is not necessarily indicative of what would have occurred if the Allkem Livent Merger had been completed as of the beginning of the periods presented, nor is it indicative of future results. The unaudited pro forma information is not necessarily indicative of operating results that would have been achieved had the acquisition been completed as of January 1, 2023 and does not intend to project the future financial results of the Company after the acquisition. The unaudited pro forma information is based on certain assumptions, which management believes are reasonable, and does not reflect the cost of any integration activities or synergies that may be derived from any integration activities. The unaudited pro forma financial results are as follows: (in Millions) Three Months Ended September 30, Nine Months Ended September 30, 2023 (Unaudited) Revenue $ 538.5 $ 1,677.7 Net income 299.0 $ 812.4

Goodwill

Goodwill	9 Months Ended
Goodwill	Sep. 30, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Goodwill The following table summarizes the changes in goodwill for the nine months ended September 30, 2024 . (in Millions) Allkem Nemaska Lithium Total Balance as of December 31, 2023 $ — $ 120.7 $ 120.7 Acquisitions - Allkem Livent Merger 1,189.2 — 1,189.2 Measurement period adjustments (15.3) (1.4) (16.7) Balance as of September 30, 2024 $ 1,173.9 $ 119.3 $ 1,293.2 See Note 4 for further details.

Revenue Recognition

Revenue Recognition	9 Months Ended
Revenue Recognition	Sep. 30, 2024
Revenue from Contract with Customer [Abstract]
Revenue Recognition	Revenue Recognition Disaggregation of revenue We disaggregate revenue from contracts with customers by geographical areas (based on product destination) and by product categories. The following table provides information about disaggregated revenue by major geographical region: (in Millions) Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Asia Pacific (1) $ 172.4 $ 163.8 $ 604.3 $ 502.4 North America (1) 22.1 31.9 65.6 124.5 Europe, Middle East & Africa 8.6 15.6 47.6 72.0 Latin America — 0.1 1.3 1.8 Consolidated Revenue $ 203.1 $ 211.4 $ 718.8 $ 700.7 1. During the three months ended September 30, 2024, countries with sales in excess of 10% of consolidated revenue consisted of China, Japan, South Korea and United States. Sales for the three months ended September 30, 2024 for China, Japan, South Korea and United States totaled $111.4 million, $33.9 million, $24.8 million, and $21.7 million, respectively. During the nine months ended September 30, 2024, countries with sales in excess of 10% of consolidated revenue consisted of China, Japan, and South Korea. Sales for the nine months ended September 30, 2024 for China, Japan, and South Korea totaled $392.4 million, $111.7 million, and $89.8 million, respectively. During the three months ended September 30, 2023, countries with sales in excess of 10% of consolidated revenue consisted of China, Japan, the United States, and South Korea. Sales for the three months ended September 30, 2023 for China, Japan, the United States, and South Korea totaled $95.6 million, $42.1 million, $30.0 million, and $20.6 million, respectively. During the nine months ended September 30, 2023, countries with sales in excess of 10% of consolidated revenue consisted of China, the United States, Japan, and South Korea. Sales for the nine months ended September 30, 2023 for China, the United States, Japan, and South Korea, totaled $274.9 million, $120.0 million, $118.2 million, and $86.9 million, respectively. For the three months ended September 30, 2024, two customers each accounted for approximately 25% of consolidated revenue and our 10 largest customers accounted in aggregate for approximately 77% of consolidated revenue. For the nine months ended September 30, 2024, two customers accounted for approximately 23% and 20%, respectively, of consolidated revenue and our 10 largest customers accounted in aggregate for approximately 73% of consolidated revenue. For the three months ended September 30, 2023, two customers accounted for approximately 28% and 25% of consolidated revenue and our 10 largest customers accounted in aggregate for approximately 78% of consolidated revenue. For the nine months ended September 30, 2023, two customers accounted for approximately 25% and 22% of consolidated revenue and our 10 largest customers accounted in aggregate for approximately 70% of consolidated revenue. A loss of any material customer could have a material adverse effect on our business, financial condition and results of operations. The following table provides information about disaggregated revenue by major product category: (in Millions) Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Lithium Hydroxide $ 85.6 $ 142.8 $ 309.3 $ 449.2 Lithium Carbonate (1) 56.0 9.0 208.5 23.6 Butyllithium and Other Lithium Specialties 39.4 59.6 130.2 227.9 Spodumene Concentrate (2) 22.1 — 70.8 — Consolidated Revenue $ 203.1 $ 211.4 $ 718.8 $ 700.7 ______________________ 1. Includes lithium carbonate by-product revenue. 2. Includes low-grade spodumene sales and minimal other products. Contract asset and contract liability balances We satisfy our obligations by transferring goods and services in exchange for consideration from customers. The timing of performance sometimes differs from the timing the associated consideration is received from the customer, thus resulting in the recognition of a contract asset or liability. Provisional pricing within certain of our customer contracts may result in recognition of a contract asset or liability. We recognize a contract liability if the customer’s payment of consideration is received prior to completion of our related performance obligation. The following table presents the opening and closing balances of our contract liabilities and current trade receivables, net of allowances from contracts with customers. (in Millions) Balance as of September 30, 2024 Balance as of December 31, 2023 (Decrease)/increase Receivables from contracts with customers, net of allowances $ 90.2 $ 106.7 $ (16.5) Contract liability - short-term 55.1 4.4 50.7 Contract liability - long-term 251.2 217.8 33.4 Performance obligations

Inventories, Net

Inventories, Net	9 Months Ended
Inventories, Net	Sep. 30, 2024
Inventory Disclosure [Abstract]
Inventories, Net	Inventories, Net Inventories consisted of the following: (in Millions) September 30, 2024 December 31, 2023 Finished goods $ 139.9 $ 59.1 Semi-finished goods 143.6 108.8 Raw materials, supplies, and other 106.1 49.6 Inventory, net $ 389.6 $ 217.5

Investments

Investments	9 Months Ended
Investments	Sep. 30, 2024
Equity Method Investments and Joint Ventures [Abstract]
Investments	Investments Investments consisted of the following: (in Millions) September 30, 2024 December 31, 2023 ESM ILiAD, LLC $ 30.1 $ 30.1 Arcadium NQSP 6.8 4.7 TLC (Naraha plant) 2.4 — Other 0.7 — Investments $ 40.0 $ 34.8 ESM ILiAD, LLC ("ESM") In the fourth quarter of 2023, the Company entered into an agreement with EnergySource Minerals, LLC ("EnergySource"), a developer of lithium projects in the Salton Sea Known Geothermal Resource Area in California, for a minority equity interest in ESM, a subsidiary of EnergySource and the parent company of ILiAD Technologies, LLC ("ILiAD Technologies"). In connection with its investment in ESM, Arcadium Lithium will have the right to license ILiAD Technologies' Integrated Lithium Adsorption Desorption ("ILiAD") technology for potential deployment at its lithium brine resources in Argentina. Arcadium Lithium accounts for its interest in ESM under ASC Topic 321, Investments – Equity Securities ("ASC 321"). Since our investment in ESM does not have a readily determinable fair value, we use the measurement alternative under ASC 321. Our investment is measured at cost less impairments, adjusted for observable price changes in orderly transactions for the identical or similar investment of the same issuer. If the Company determines that an indicator of impairment or upward adjustment is present, an adjustment is recorded, which is measured as the difference between carrying value and estimated fair value. Estimated fair value is generally determined using an income approach on discounted cash flows or negotiated transaction values. As of September 30, 2024 and December 31, 2023, the carrying amount of our investment in ESM was $30.1 million. Toyotsu Lithium Corporation ("TLC") The Company owns 49% of the Class A voting shares and 100% of the Class B non-voting shares in TLC. Toyota Tsusho Corporation ("TTC") owns 51% of the Class A voting shares. As a result, the Company has a 75% economic interest and a 49% ownership interest in TLC and TTC has the remaining 25% economic interest and 51% ownership interest in TLC. TLC constructed and now operates the Naraha Lithium Hydroxide Plant (the "Naraha Plant"), located in Japan. The technical grade lithium carbonate feedstock for the plant is sourced from the Company’s Olaroz Plant. The Company accounts for its interest in TLC as an equity method investment because it does not have control but has significant influence. This is evidenced by the Company having 2 of the 5 board members while decisions are made by a majority. In addition to capital contributions made through its investment in TLC, Allkem has also provided past funding through loans. At the Acquisition Date, the carrying values of the investment in TLC and a fully reserved loan receivable were zero and fair value was deemed to be equal to carrying value. For the three and nine months ended September 30, 2024, we recorded a $5.9 million loss related to our interest in TLC to Equity in net loss of unconsolidated affiliates in our condensed consolidated statements of operations. At September 30, 2024, the carrying value of our interest in TLC and the loan receivable was zero and $2.4 million, respectively. Nemaska Lithium Inc. ("Nemaska Lithium", or "NLI") Nemaska Lithium, domiciled in Canada and headquartered in Montreal, Québec, is a non-public lithium company not yet in the production stage. It is a development company aiming to vertically integrate, from extracting, processing and concentrating spodumene to conversion of spodumene into battery-grade lithium hydroxide, primarily intended for EV and other energy storage applications. Its primary assets are construction in progress and intangibles principally related to intellectual property. Nemaska Lithium intends to develop the Whabouchi spodumene mine and concentrator in the James Bay region of Québec and a lithium hydroxide conversion plant in Bécancour, Québec (collectively, the "Nemaska Lithium Project"). As a developing company and to fund the Nemaska Lithium Project, Nemaska Lithium is reliant on securing financing from its shareholders through share subscriptions. On October 18, 2023, we entered into an amendment to our shareholders agreement with Nemaska Lithium, and also amendments to certain related service agreements. The amendments to these agreements provide QLP with control of certain substantive participating rights, and as such, the Company began to consolidate Nemaska Lithium as of October 18, 2023. Nemaska Lithium is a development company which, as of the October 18, 2023 consolidation date, met the U.S. GAAP definition of a business and, as such, the Company remeasured its equity interest in Nemaska, including the noncontrolling interest of Investissement Québec ("IQ"), at fair value as of the consolidation date. We estimated the fair value of IQ's noncontrolling interest by multiplying the total fair value of Nemaska Lithium equity by IQ's equity ownership interest and also considered any discounts for lack of control and marketability. The fair value of the assets and liabilities of Nemaska Lithium assumed under business combination accounting guidance for the Nemaska Lithium consolidation, including the impact of income taxes, is preliminary. The preliminary fair value allocation is subject to change for up to one year subsequent to the October 18, 2023 consolidation date of Nemaska Lithium. Determining the fair value of the assets and liabilities of Nemaska Lithium requires judgment and certain assumptions to be made, the most significant of these being related to the valuation of Nemaska Lithium's mining properties and rights. Nemaska Lithium is consolidated on a one-quarter lag basis. Before October 18, 2023, the Company accounted for its 50% interest in Nemaska Lithium as an equity method investment on a one-quarter lag basis and it was included in Investments in our consolidated balance sheets. The carrying amount of our interest in Nemaska Lithium was $437.1 million as of December 31, 2022 under equity method investment accounting. For the three and nine months ended September 30, 2023 we recorded a $6.7 million and $22.0 million loss related to our interest in Nemaska Lithium to Equity in net loss of unconsolidated affiliate in our condensed consolidated statements of operations. Arcadium's cash and cash equivalents balance in its condensed consolidated balance sheet as of September 30, 2024 includes Nemaska Lithium's cash of $42 million at June 30, 2024 as Nemaska Lithium is consolidated on a one-quarter lag. All cash at Nemaska Lithium will be used for capital expenditures and operating expenses of the Nemaska Lithium Project. As of September 30, 2024, Nemaska Lithium received cash of $225.0 million related to advance payments in connection with a customer supply agreement repayable in equal quarterly installments beginning in January 2027 and ending in October 2031. The related liability, consolidated on a one-quarter lag basis, is $161.3 million debt and $63.7 million contract liability as of September 30, 2024, see Note 15 for details. A total of $350.0 million in prepayments are expected from the customer with final prepayment expected in early 2025. In the third quarter of 2024, the Company contributed cash of $43.9 million to Nemaska Lithium which, due to one-quarter lag reporting, is not yet recorded in our consolidation of Nemaska. The balance is recorded to Other assets - noncurrent because the cash is expected to be used by Nemaska primarily for capital expenditures. IQ contemporaneously made an equal contribution in the third quarter of 2024 which, due to one-quarter lag reporting, is not recorded in our consolidation of Nemaska. In the fourth quarter of 2024, the Company invested cash of $22.0 million in Nemaska Lithium under a subscription agreement dated October 9, 2024. IQ, which owns the remaining 50% interest in Nemaska Lithium, contemporaneously made an equal contribution and Arcadium's ownership stake is not changed pursuant to the additional investment. Sales de Jujuy Pte Ltd and Sales de Jujuy S.A. The Company has an interest of 72.68% in Sales de Jujuy Pte Ltd ("SDJ Pte"), 66.5% in Sales de Jujuy S.A. ("SDJ"), the legal entities which operate the Olaroz Lithium Facility (the "Olaroz Plant"). Located in the Jujuy Province of northern Argentina, the Olaroz Plant produces lithium carbonate chemicals for the battery, technical and chemical markets. The Olaroz Plant is operated through SDJ, which is a 91.5% owned subsidiary of SDJ Pte, a Singaporean company owned by Arcadium (72.68%) and Toyotsu Lithium Pte Ltd. (27.32%), an affiliated company of TTC. Jujuy Energia y Minera Sociedad del Estado ("JEMSE") owns the remaining 8.5% of SDJ. Consequently, the effective equity ownership of the Olaroz Plant is 66.5% by Arcadium, 25% by TTC, and 8.5% by JEMSE. As of September 30, 2024, Arcadium had restricted cash of $18.1 million on deposit with Mizuho as collateral for the Project Loan Facility and classified within Other non-current assets in its condensed consolidated balance sheets. See Note 15 for details. Arcadium's cash and cash equivalents balance in its condensed consolidated balance sheet as of September 30, 2024 includes $42.6 million held by the entities discussed above. Arcadium funded JEMSE’s equity contributions in SDJ with an interest-free loan (the "JEMSE Receivable") to be repaid by JEMSE out of 33% of the dividends it receives from SDJ. The fair value of the non-current receivable is $5.0 million as of September 30, 2024.

Partially-Owned Subsidiaries an

Partially-Owned Subsidiaries and Noncontrolling Interests	9 Months Ended
Partially-Owned Subsidiaries and Noncontrolling Interests	Sep. 30, 2024
Equity Method Investments and Joint Ventures [Abstract]
Partially-Owned Subsidiaries and Noncontrolling Interests	Investments Investments consisted of the following: (in Millions) September 30, 2024 December 31, 2023 ESM ILiAD, LLC $ 30.1 $ 30.1 Arcadium NQSP 6.8 4.7 TLC (Naraha plant) 2.4 — Other 0.7 — Investments $ 40.0 $ 34.8 ESM ILiAD, LLC ("ESM") In the fourth quarter of 2023, the Company entered into an agreement with EnergySource Minerals, LLC ("EnergySource"), a developer of lithium projects in the Salton Sea Known Geothermal Resource Area in California, for a minority equity interest in ESM, a subsidiary of EnergySource and the parent company of ILiAD Technologies, LLC ("ILiAD Technologies"). In connection with its investment in ESM, Arcadium Lithium will have the right to license ILiAD Technologies' Integrated Lithium Adsorption Desorption ("ILiAD") technology for potential deployment at its lithium brine resources in Argentina. Arcadium Lithium accounts for its interest in ESM under ASC Topic 321, Investments – Equity Securities ("ASC 321"). Since our investment in ESM does not have a readily determinable fair value, we use the measurement alternative under ASC 321. Our investment is measured at cost less impairments, adjusted for observable price changes in orderly transactions for the identical or similar investment of the same issuer. If the Company determines that an indicator of impairment or upward adjustment is present, an adjustment is recorded, which is measured as the difference between carrying value and estimated fair value. Estimated fair value is generally determined using an income approach on discounted cash flows or negotiated transaction values. As of September 30, 2024 and December 31, 2023, the carrying amount of our investment in ESM was $30.1 million. Toyotsu Lithium Corporation ("TLC") The Company owns 49% of the Class A voting shares and 100% of the Class B non-voting shares in TLC. Toyota Tsusho Corporation ("TTC") owns 51% of the Class A voting shares. As a result, the Company has a 75% economic interest and a 49% ownership interest in TLC and TTC has the remaining 25% economic interest and 51% ownership interest in TLC. TLC constructed and now operates the Naraha Lithium Hydroxide Plant (the "Naraha Plant"), located in Japan. The technical grade lithium carbonate feedstock for the plant is sourced from the Company’s Olaroz Plant. The Company accounts for its interest in TLC as an equity method investment because it does not have control but has significant influence. This is evidenced by the Company having 2 of the 5 board members while decisions are made by a majority. In addition to capital contributions made through its investment in TLC, Allkem has also provided past funding through loans. At the Acquisition Date, the carrying values of the investment in TLC and a fully reserved loan receivable were zero and fair value was deemed to be equal to carrying value. For the three and nine months ended September 30, 2024, we recorded a $5.9 million loss related to our interest in TLC to Equity in net loss of unconsolidated affiliates in our condensed consolidated statements of operations. At September 30, 2024, the carrying value of our interest in TLC and the loan receivable was zero and $2.4 million, respectively. Nemaska Lithium Inc. ("Nemaska Lithium", or "NLI") Nemaska Lithium, domiciled in Canada and headquartered in Montreal, Québec, is a non-public lithium company not yet in the production stage. It is a development company aiming to vertically integrate, from extracting, processing and concentrating spodumene to conversion of spodumene into battery-grade lithium hydroxide, primarily intended for EV and other energy storage applications. Its primary assets are construction in progress and intangibles principally related to intellectual property. Nemaska Lithium intends to develop the Whabouchi spodumene mine and concentrator in the James Bay region of Québec and a lithium hydroxide conversion plant in Bécancour, Québec (collectively, the "Nemaska Lithium Project"). As a developing company and to fund the Nemaska Lithium Project, Nemaska Lithium is reliant on securing financing from its shareholders through share subscriptions. On October 18, 2023, we entered into an amendment to our shareholders agreement with Nemaska Lithium, and also amendments to certain related service agreements. The amendments to these agreements provide QLP with control of certain substantive participating rights, and as such, the Company began to consolidate Nemaska Lithium as of October 18, 2023. Nemaska Lithium is a development company which, as of the October 18, 2023 consolidation date, met the U.S. GAAP definition of a business and, as such, the Company remeasured its equity interest in Nemaska, including the noncontrolling interest of Investissement Québec ("IQ"), at fair value as of the consolidation date. We estimated the fair value of IQ's noncontrolling interest by multiplying the total fair value of Nemaska Lithium equity by IQ's equity ownership interest and also considered any discounts for lack of control and marketability. The fair value of the assets and liabilities of Nemaska Lithium assumed under business combination accounting guidance for the Nemaska Lithium consolidation, including the impact of income taxes, is preliminary. The preliminary fair value allocation is subject to change for up to one year subsequent to the October 18, 2023 consolidation date of Nemaska Lithium. Determining the fair value of the assets and liabilities of Nemaska Lithium requires judgment and certain assumptions to be made, the most significant of these being related to the valuation of Nemaska Lithium's mining properties and rights. Nemaska Lithium is consolidated on a one-quarter lag basis. Before October 18, 2023, the Company accounted for its 50% interest in Nemaska Lithium as an equity method investment on a one-quarter lag basis and it was included in Investments in our consolidated balance sheets. The carrying amount of our interest in Nemaska Lithium was $437.1 million as of December 31, 2022 under equity method investment accounting. For the three and nine months ended September 30, 2023 we recorded a $6.7 million and $22.0 million loss related to our interest in Nemaska Lithium to Equity in net loss of unconsolidated affiliate in our condensed consolidated statements of operations. Arcadium's cash and cash equivalents balance in its condensed consolidated balance sheet as of September 30, 2024 includes Nemaska Lithium's cash of $42 million at June 30, 2024 as Nemaska Lithium is consolidated on a one-quarter lag. All cash at Nemaska Lithium will be used for capital expenditures and operating expenses of the Nemaska Lithium Project. As of September 30, 2024, Nemaska Lithium received cash of $225.0 million related to advance payments in connection with a customer supply agreement repayable in equal quarterly installments beginning in January 2027 and ending in October 2031. The related liability, consolidated on a one-quarter lag basis, is $161.3 million debt and $63.7 million contract liability as of September 30, 2024, see Note 15 for details. A total of $350.0 million in prepayments are expected from the customer with final prepayment expected in early 2025. In the third quarter of 2024, the Company contributed cash of $43.9 million to Nemaska Lithium which, due to one-quarter lag reporting, is not yet recorded in our consolidation of Nemaska. The balance is recorded to Other assets - noncurrent because the cash is expected to be used by Nemaska primarily for capital expenditures. IQ contemporaneously made an equal contribution in the third quarter of 2024 which, due to one-quarter lag reporting, is not recorded in our consolidation of Nemaska. In the fourth quarter of 2024, the Company invested cash of $22.0 million in Nemaska Lithium under a subscription agreement dated October 9, 2024. IQ, which owns the remaining 50% interest in Nemaska Lithium, contemporaneously made an equal contribution and Arcadium's ownership stake is not changed pursuant to the additional investment. Sales de Jujuy Pte Ltd and Sales de Jujuy S.A. The Company has an interest of 72.68% in Sales de Jujuy Pte Ltd ("SDJ Pte"), 66.5% in Sales de Jujuy S.A. ("SDJ"), the legal entities which operate the Olaroz Lithium Facility (the "Olaroz Plant"). Located in the Jujuy Province of northern Argentina, the Olaroz Plant produces lithium carbonate chemicals for the battery, technical and chemical markets. The Olaroz Plant is operated through SDJ, which is a 91.5% owned subsidiary of SDJ Pte, a Singaporean company owned by Arcadium (72.68%) and Toyotsu Lithium Pte Ltd. (27.32%), an affiliated company of TTC. Jujuy Energia y Minera Sociedad del Estado ("JEMSE") owns the remaining 8.5% of SDJ. Consequently, the effective equity ownership of the Olaroz Plant is 66.5% by Arcadium, 25% by TTC, and 8.5% by JEMSE. As of September 30, 2024, Arcadium had restricted cash of $18.1 million on deposit with Mizuho as collateral for the Project Loan Facility and classified within Other non-current assets in its condensed consolidated balance sheets. See Note 15 for details. Arcadium's cash and cash equivalents balance in its condensed consolidated balance sheet as of September 30, 2024 includes $42.6 million held by the entities discussed above. Arcadium funded JEMSE’s equity contributions in SDJ with an interest-free loan (the "JEMSE Receivable") to be repaid by JEMSE out of 33% of the dividends it receives from SDJ. The fair value of the non-current receivable is $5.0 million as of September 30, 2024.

Property, Plant and Equipment,

Property, Plant and Equipment, Net	9 Months Ended
Property, Plant and Equipment, Net	Sep. 30, 2024
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment, Net	Property, Plant and Equipment, Net Property, plant and equipment consisted of the following: (in Millions) September 30, 2024 December 31, 2023 Land and land improvements $ 334.7 $ 106.2 Buildings 985.3 134.9 Machinery and equipment 985.6 420.7 Mineral rights 3,279.6 560.0 Construction in progress 2,009.5 1,284.4 Total cost $ 7,594.7 $ 2,506.2 Accumulated depreciation (345.5) (269.1) Property, plant and equipment, net $ 7,249.2 $ 2,237.1 Depreciation is calculated principally on a straight-line basis over the estimated useful lives of the assets or a units-of-production basis based on the rate of depletion of reserves. Land is not depreciated. The major classifications of property, equipment and software, including their respective principal depreciation and amortization method and expected useful lives, consisted of the following: Asset type Depreciation and amortization method Useful Life Land N/A — Land improvements Straight-line 20 years Buildings Straight-line 20-40 years Mineral rights Units-of-production Based on rate of depletion of reserves Mining extraction equipment Units-of-production Based on rate of depletion of reserves Leased plant and equipment Straight-line Lease period (1-10.5 years) Other machinery and equipment Straight-line 3-18 years Software Straight-line 3-10 years Depreciation expense was $74.6 million and $21.5 million for the nine months ended September 30, 2024 and 2023, respectively. Long-Lived Asset Impairment On September 4, 2024, Arcadium Lithium announced that it will suspend Stage 4A waste stripping, and any expansionary investment beyond Stage 3, at its Mt Cattlin spodumene operation in Western Australia given the decline in spodumene prices. As a result, the Company plans to place the Mt Cattlin site into care and maintenance by the end of the first half of 2025 after it completes Stage 3 mining and ore processing. The Company does not intend to close Mt Cattlin. Care and maintenance will keep the mine and processing facilities in a position to potentially resume operations when market conditions become more favorable. The Company will also continue to explore the viability of underground mining at the Mt Cattlin site, which could potentially extend the remaining mine life.

Restructuring and Other Charges

Restructuring and Other Charges	9 Months Ended
Restructuring and Other Charges	Sep. 30, 2024
Restructuring and Related Activities [Abstract]
Restructuring and Other Charges	Restructuring and Other Charges The following table shows other charges included in Restructuring and other charges in the condensed consolidated statements of operations: Three Months Ended September 30, Nine Months Ended September 30, (in Millions) 2024 2023 2024 2023 Restructuring charges: Severance-related and exit costs $ 0.6 $ — $ 14.7 $ 2.4 Other charges: Costs related to the Allkem Livent Merger 12.2 13.6 99.0 32.3 Bessemer City plant fire - gain, net of insurance recoveries — (5.0) — — Other (3.1) 0.1 (2.3) 0.3 Total Restructuring and other charges $ 9.7 $ 8.7 $ 111.4 $ 35.0

Other gains_(losses)

Other gains/(losses)	9 Months Ended
Other gains/(losses)	Sep. 30, 2024
Other Income and Expenses [Abstract]
Other gains/(losses)	Other gains/(losses) The following table shows amounts included in Other gains/(losses) in the condensed consolidated statements of operations: Three Months Ended September 30, Nine Months Ended September 30, (in Millions) 2024 2023 2024 2023 Blue Chip Swap gains: (1) Non-recurring - SDV and MdA Holdings LLC (2) $ 8.7 $ 10.0 $ 45.2 $ 21.4 Recurring - SDJ and MdA 5.7 — 19.7 — Total Blue Chip Swap gains 14.4 10.0 64.9 21.4 Foreign currency remeasurement gains/(losses): Remeasurement gains on U.S. dollar denominated cash held by foreign currency functional subsidiary — — 14.3 — All other foreign currency remeasurement gains/(losses) (3) 30.9 (11.2) 123.7 (16.1) Total Foreign currency remeasurement gains/(losses) 30.9 (11.2) 138.0 (16.1) Loss on trading securities (0.5) — (0.9) — Total Other gains/(losses) $ 44.8 $ (1.2) $ 202.0 $ 5.3 ___________________________ 1. See Note 2 for details. 2. Represents the non-recurring gain from the sale in Argentina pesos of Argentina Sovereign U.S. dollar-denominated bonds due to the divergence of Argentina's Blue Chip Swap market exchange rate from the official rate. 3.

Income Taxes

Income Taxes	9 Months Ended
Income Taxes	Sep. 30, 2024
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes We determine our interim tax provision using an estimated annual effective tax rate methodology ("EAETR") in accordance with U.S. GAAP. The EAETR is applied to the year-to-date ordinary income, exclusive of discrete items. The tax effects of discrete items are then included to arrive at the total reported interim tax provision. The determination of the EAETR is based upon a number of estimates, including the estimated annual pretax ordinary income in each tax jurisdiction in which we operate. As our projections of ordinary income change throughout the year, the EAETR will change period-to-period. The tax effects of discrete items are recognized in the tax provision in the period they occur in accordance with U.S. GAAP. Depending on various factors, such as the item’s significance in relation to total income and the rate of tax applicable in the jurisdiction to which it relates, discrete items in any quarter can materially impact the reported effective tax rate. As a global enterprise, our tax expense can be impacted by changes in tax rates or laws, the finalization of tax audits and reviews, as well as other factors. As a result, there can be significant volatility in interim tax provisions.

Asset Retirement Obligations

Asset Retirement Obligations	9 Months Ended
Asset Retirement Obligations	Sep. 30, 2024
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations	Asset Retirement Obligations Legacy Allkem asset retirement obligations acquired in the Allkem Livent Merger were recorded at fair value on the Acquisition Date and consist of $7.3 million, $1.5 million and $1.0 million related to the Mt Cattlin spodumene mine in Western Australia, the Olaroz lithium brine extraction facility in Jujuy, Argentina and the Sal de Vida lithium brine extraction facility (currently under development) in Catamarca, Argentina, respectively.

Debt

Debt	9 Months Ended
Debt	Sep. 30, 2024
Debt Disclosure [Abstract]
Debt	Debt Debt consists of the following: Interest Rate Percentage Maturity September 30, 2024 December 31, 2023 (in Millions) SOFR borrowings Base rate borrowings Revolving Credit Facility (1) 6.70% 8.75% 2027 $ 99.0 $ — 4.125% Convertible Senior Notes due 2025 4.125% 2025 245.8 245.8 Transaction costs - 2025 Notes (1.2) (2.4) Nemaska - Prepayment agreement - tranche 1 (2) 8.9% 75.0 75.0 Discount - Prepayment agreement (16.2) (19.8) Nemaska - Prepayment agreement - tranche 2 (2) 9.4% 150.0 — Discount - Prepayment agreement (47.5) — Nemaska - Other 0.5 3.4 Debt assumed in Allkem Livent Merger (3) Project Loan Facility - Stage 2 of Olaroz Plant 2.61% 2029 135.0 — Affiliate Loans with TTC 15.29% 2030 81.5 — Affiliate Loan with TLP 10.34% 2026 2.5 — Total debt assumed in Allkem Livent Merger 219.0 — Subtotal long-term debt (including current maturities) 724.4 302.0 Less current maturities (288.4) (2.4) Total long-term debt $ 436.0 $ 299.6 ______________________________ 1. As of September 30, 2024 and December 31, 2023, there were $20.7 million and $15.5 million, respectively, in letters of credit outstanding under our Revolving Credit Facility and $380.3 million and $484.5 million available funds as of September 30, 2024 and December 31, 2023, respectively. Fund availability is subject to the Company meeting its debt covenants. 2. Represents advance payments in connection with customer supply agreement which do not have a contractual interest rate or bear any actual interest and are repayable in equal quarterly installments beginning in January 2027 and ending in October 2031. Represents U.S. GAAP imputed interest rate. 3. On September 10, 2024, SDJ paid the outstanding principal balance of $9.1 million to repay Stage 1 of the Olaroz Plan Project Loan Facility in its entirety. On May 30, 2024, SDV paid the outstanding principal balance of $47.0 million, a prepayment fee of $0.9 million and accrued interest and commitment fees of $1.3 million to repay the Sal de Vida Project Financing Facility in its entirety. 4.125% Convertible Senior Notes due 2025 In 2020, the Company issued $245.8 million in aggregate principal amount of 4.125% Convertible Senior Notes due in July 2025 (the "2025 Notes"). The 2025 Notes are our general unsecured senior obligations. Total net cash proceeds received were $238.2 million net of $7.6 million of third-party transaction costs, including initial purchasers' discounts and commissions. The Company used or will use the net proceeds received to finance or refinance eligible green projects designed to align with the provisions of the International Capital Market Association Green Bond Principles 2018. Each $1,000 of principal of the 2025 Notes was initially convertible into 114.4885 shares of common stock of Livent Corporation, which was equivalent to an initial conversion price of $8.73 per share, subject to adjustment upon the occurrence of specified events. Following the effectiveness of that certain First Supplemental Indenture, dated as of January 4, 2024, by and among the Company, Livent Corporation and U.S. Bank Trust Company, National Association, each $1,000 of principal of the 2025 Notes is convertible into 275.459331 shares of our ordinary shares, which is equivalent to a conversion price of $3.63 per share, subject to adjustment upon the occurrence of specified events. We may redeem for cash all or any portion of the 2025 Notes, at our option, if the last reported sale price of our ordinary shares has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period (including the last trading day of such period) ending on, and including, the trading day immediately preceding the date on which we provide notice of redemption at a redemption price equal to 100% of the principal amount of the 2025 Notes to be redeemed, plus accrued and unpaid interest. Holders of the 2025 Notes may convert their notes at any time, at their option, on or after January 15, 2025. Further, holders of the 2025 Notes may convert their notes at any time, at their option, prior to January 15, 2025 only under the following circumstances: (1) during any calendar quarter commencing after September 30, 2020 (and only during such calendar quarter), if the last reported sale price of our ordinary shares for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each trading day; (2) during the five-business day period after any five-consecutive trading day period in which the trading price per $1,000 principal amount of the 2025 Notes for each trading day of such period is less than 98% of the product of the last reported sale price of our ordinary shares and the conversion rate on each such trading day, (3) if we call any or all of the 2020 Notes for redemption, at any time prior to the close of business on the scheduled trading day immediately preceding the redemption date or (4) if specified corporate events occur. Upon conversion, the 2025 Notes will be settled in cash, shares of our ordinary shares or a combination thereof, at our election. If a fundamental change occurs prior to the maturity date, holders of the 2025 Notes may require us to repurchase all or a portion of their 2025 Notes for cash at a repurchase price equal to 100% of the principal amount plus any accrued and unpaid interest. In addition, if specific corporate events occur prior to the maturity date or if we deliver a notice of redemption, we will increase the conversion rate for a holder who elects to convert its 2025 Notes in connection with such an event or notice of redemption in certain circumstances. The last reported sale price of our ordinary shares for at least 20 trading days (whether or not consecutive) during the period of 30 consecutive trading days ending on, and including, September 30, 2024 was not greater than or equal to 130% of the conversion price as adjusted for the Allkem Livent Merger, which is $4.72, on each trading day, and as a result, the holders do not have the option to convert all or any portion of their 2025 Notes through December 31, 2024. The conversion rate for the 2025 Notes is 275.4593 ordinary shares of Arcadium Lithium per $1,000 principal amount of 2025 Notes. The 2025 Notes mature in July 2025 and were reclassified to current portion of long-term debt in the third quarter of 2024. On the July 15, 2025 maturity date, we are required to cash settle any outstanding 2025 Notes that have not otherwise been redeemed or converted. The Company recognized non-cash interest related to the amortization of transaction costs for the 2025 Notes of $0.4 million and $1.1 million for the three and nine months ended September 30, 2024, respectively, all of which was capitalized. The Company recorded $2.5 million and $7.5 million of accrued interest expense related to the principal amount for the three and nine months ended September 30, 2024, respectively, all of which was capitalized. Amended and Restated Credit Agreement, (the "Revolving Credit Facility") On January 4, 2024, Livent Corporation, Livent USA Corp., the Company, Arcadium Lithium Financing IRL Limited ("FinCo") and Irish IntermediateCo (collectively, the "Borrowers" and, each, a "Borrower"), the guarantors party thereto from time to time (the "Guarantors"), the lenders party thereto (the "Lenders") and issuing banks party thereto and Citibank, N.A., as administrative agent (the "Administrative Agent") for the Lenders, entered into a Joinder and First Amendment (the "Credit Agreement Amendment") to that certain Amended and Restated Credit Agreement, dated as of September 1, 2022, among Livent, Livent USA Corp., the guarantors party thereto from time to time, the lenders party thereto from time to time and the Administrative Agent (the "Credit Agreement" and as amended by the Credit Agreement Amendment, the Amended Credit Agreement"). The Credit Agreement Amendment provided for, among other things, (i) the addition of Arcadium, Irish IntermediateCo and FinCo as borrowers and obligors under the Amended Credit Agreement and (ii) the assignment of certain of Livent Corporation's rights and obligations (including information reporting obligations) under the Amended Credit Agreement to Arcadium. The Revolving Credit Facility provides for a $500 million senior secured revolving credit facility, $50 million of which is available for the issuance of letters of credit for the account of the Borrowers, with an option to request, and subject to each Lender’s sole discretion, that the aggregate revolving credit commitments be increased to up to $700 million. The issuance of letters of credit and the proceeds of revolving credit loans made pursuant to the Revolving Credit Facility may be used for general corporate purposes, including capital expenditures and permitted acquisitions. Revolving loans under the Revolving Credit Facility will bear interest at a floating rate, which will be (i) a base rate, (ii) Adjusted Term Secured Overnight Financing Rate ("SOFR") (defined as the forward-looking SOFR CME Group Benchmark Administration Limited plus 0.10% per annum subject to a floor of zero) or (iii) Euro Interbank Offered Rate ("EURIBOR"), plus, in each case, an applicable margin, as determined in accordance with the provisions of the Revolving Credit Facility. The Revolving Credit Facility includes a quarterly commitment fee on the average daily unused amount of each Lender’s revolving credit commitment at a rate equal to an applicable percentage based on the Company’s first lien leverage ratio. The initial commitment fee is 0.25% per annum. Amounts under the Revolving Credit Facility may be borrowed, repaid and re-borrowed from time to time until the final maturity date on September 1, 2027. Voluntary prepayments and commitment reductions are permitted at any time without payment of any prepayment fee upon proper notice and subject to minimum dollar amounts. Certain of the Borrowers’ domestic subsidiaries (the "Guarantors") guarantee the obligations of the Borrowers under the Revolving Credit Facility. The obligations of the Borrower and the Guarantors are secured by all of the assets of the Borrowers and the Guarantors, including the Borrowers’ facility and real estate in Bessemer City, North Carolina, subject to certain exceptions and exclusions. We recorded $0.8 million of incremental deferred financing costs in the condensed consolidated balance sheets for the Revolving Credit Facility commitment and legal fees and a zero and $0.2 million loss on debt extinguishment in the condensed consolidated statements of operations for the three and nine months ended September 30, 2024, respectively, for the write off of existing deferred financing costs to recognize a partial change in syndication related to the Revolving Credit Facility. The carrying value of our deferred financing costs was $2.3 million as of September 30, 2024 and is recorded to Other assets in our condensed consolidated balance sheet. Covenants The Credit Agreement contains certain affirmative and negative covenants that are binding on us and our subsidiary, Livent USA Corp., as borrowers (the "Borrowers") and their subsidiaries, including, among others, restrictions (subject to exceptions and qualifications) on the ability of the Borrowers and their subsidiaries to create liens, to undertake fundamental changes, to incur debt, to sell or dispose of assets, to make investments, to make restricted payments such as dividends, distributions or equity repurchases, to change the nature of their businesses, to enter into transactions with affiliates and to enter into certain restrictive agreements. Furthermore, the Borrowers are subject to financial covenants regarding leverage (measured as the ratio of debt to adjusted earnings) and interest coverage (measured as the ratio of adjusted earnings to interest expense). Our maximum allowable first lien leverage ratio is 3.5 as of September 30, 2024. Our minimum allowable interest coverage ratio is 3.5. We were in compliance with all requirements of the covenants as of September 30, 2024. Debt assumed as a result of Allkem Livent Merger The following is a summary of Allkem's indebtedness that Arcadium Lithium assumed as a result of the Allkem Livent Merger. Project Financing Facility Galaxy Lithium (SAL DE VIDA) S.A. ("SDV"), which is owned 100% by Arcadium, entered into a project financing facility with the International Finance Corporation related to the Sal de Vida development project ("Sal de Vida") in Argentina (the "Project Financing Facility"). The Project Financing Facility originally provided for a total of $180.0 million in limited recourse, sustainability-linked green project financing maturing in March 2033. On May 30, 2024, SDV paid the lender the outstanding principal balance of $47.0 million, a prepayment fee of $0.9 million and accrued interest and commitment fees of $1.3 million to repay the Project Financing Facility in its entirety. Project Loan Facility SDJ has a project loan facility with Mizuho Bank related to the Olaroz Plant (the "Project Loan Facility"): • On September 10, 2024, SDJ paid the lender the outstanding principal balance of $9.1 million, to repay the Project Loan Facility for Stage 1 of the Olaroz Plant in its entirety. • The Project Loan Facility for Stage 2 of the Olaroz project had an outstanding balance of $135.0 million as of September 30, 2024. The interest rate for the Stage 2 loan is a fixed rate of 2.6119% per annum until expiry in March 2029. As of September 30, 2024, Arcadium had restricted cash of $18.1 million on deposit with Mizuho as collateral for the Project Loan Facility and classified within Other non-current assets in its condensed consolidated balance sheet. As of September 30, 2024, Arcadium is also required to reserve $101.3 million of its cash and cash equivalents in support of a guarantee to TTC associated with the Stage 2 Project Loan Facility for the Olaroz Plant. Arcadium would incur a 2.5% fee for permitted reductions to this reserve. Affiliate Loans With TTC SDJ has eleven loans with TTC related to the Olaroz Plant originally providing for a total of $93.0 million in principal. As of September 30, 2024, the loans have an outstanding principal balance of $81.5 million and are payable ranging from July 2024 until March 2030.

Share-based Compensation

Share-based Compensation	9 Months Ended
Share-based Compensation	Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]
Share-based Compensation	Share-based Compensation Arcadium Lithium plc Omnibus Incentive Plan (the "Arcadium Plan") As of September 30, 2024, there were 64,548,000 Arcadium ordinary shares authorized for issuance under the Arcadium Plan. The Arcadium Plan provides for the grant of a variety of cash and equity awards to officers, directors, employees and consultants, including share options, restricted shares, restricted share units (including performance units), share appreciation rights, and management incentive awards. The Compensation Committee of the Arcadium Board of Directors (the "Arcadium Committee") has the authority to amend the Arcadium Plan at any time, approve financial targets, award grants, establish performance objectives and conditions and the times and conditions for payment of awards. Share options granted under the Arcadium Plan may be incentive or non-qualified share options. The exercise price for share options may not be less than the fair market value of the share at the date of grant. Awards granted under the Arcadium Plan vest or become exercisable or payable at the time designated by the Arcadium Committee. The options granted in 2024 will vest on the first, second and third anniversaries of the date of grant, subject generally to continued employment, and cost is recognized over the vesting period. Incentive and non-qualified options granted under the Arcadium Plan expire not later than 10 years from the grant date. Under the Arcadium Plan, awards of restricted share units ("RSUs") vest over periods designated by the Arcadium Committee. The RSUs granted in 2024 to employees will vest equally on the first, second and third anniversaries of the grant date, subject generally to continued employment, and cost is recognized over the vesting period. The RSUs granted to non-employee directors in 2024 vest at the Company's next annual meeting of shareholders following the grant date. Compensation cost is recognized over the vesting periods based on the market value of Arcadium ordinary shares on the grant date of the award. Allkem Replacement Awards Pursuant to the Allkem Transaction Agreement, the equity awards of Allkem (including performance rights) outstanding as of immediately prior to the closing of the Allkem Livent Merger were converted into equity awards denominated in shares of Arcadium ordinary shares. The Company issued time-based vesting restricted shares in connection with the conversion of such awards. The estimated fair value of the portion of the Allkem equity awards for which the required service period had been completed at the time of the closing of the Allkem Livent Merger was treated as purchase consideration. The remaining estimated fair value is recorded as compensation expense over the remainder of the service period associated with the awards. The Allkem Replacement Awards are authorized for issuance under the Arcadium Plan. Treatment of Equity Awards in the Rio Tinto Transaction At the completion of the Rio Tinto Transaction, the Company’s outstanding equity awards will be treated as follows: • Restricted Stock Units: Each outstanding RSU that is held by a non-employee director will be cancelled and converted into the right to receive an amount in cash, without interest, equal to $5.85 per Company share. Each other outstanding RSU will be cancelled and exchanged for an award of restricted stock units with respect to a number of ordinary shares of either Rio Tinto plc or Rio Tinto Limited (each, a "Listed Share"), determined by multiplying the number of Company shares subject to such RSU by the Equity Award Conversion Ratio (as defined in the Rio Tinto Transaction Agreement). • Restricted Share Rights (or "Allkem Replacement Awards" per the Allkem Transaction Agreement): Each outstanding restricted share right with respect to Company shares, whether vested or unvested (each, a "Restricted Share Right"), will be cancelled and exchanged for an award of restricted share rights with respect to a number of Listed Shares, determined by multiplying the number of Company shares subject to such Restricted Share Right by the Equity Award Conversion Ratio. • Stock Options: Each outstanding stock option with respect to the Company’s shares, whether vested or unvested (each, a "Company Stock Option"), will be cancelled and exchanged for an option to purchase a number of applicable Listed Shares determined by multiplying (i) the number of Company shares subject to such Company Stock Option by (ii) the Equity Award Conversion Ratio, rounded down to the nearest whole share. Such stock option will have a per-share exercise price determined by dividing (i) the exercise price per Company share at which such Company Stock Option was exercisable immediately prior to the closing by (ii) the Equity Award Conversion Ratio, rounded up to the nearest whole cent. Legacy Livent Awards As of September 30, 2024, there were 6,579,305 Arcadium ordinary shares authorized for issuance upon the exercise or settlement of the Legacy Livent Awards. Share Compensation We recognized the following share compensation expense for Legacy Livent Awards and awards under the Arcadium Plan: Three Months Ended September 30, Nine Months Ended September 30, (in Millions) 2024 Share Option Expense, net of taxes of $0.1 and $0.3 $ 0.7 $ 1.9 Restricted Share Expense, net of taxes of $0.1 and $1.2 2.8 19.8 Performance-Based Restricted Share Expense, net of taxes of zero and zero — 0.4 Total Share Compensation Expense, net of taxes of $0.2 and $1.5 (1) $ 3.5 $ 22.1 ____________________ (1) Gross share compensation charges of $3.4 million and $0.5 million were recorded to Selling, general and administrative expenses and Restructuring and other charges, respectively, in our condensed consolidated statements of operations for the three months ended September 30, 2024. Gross share compensation charges of $9.1 million and $14.5 million were recorded to Selling, general and administrative expenses and Restructuring and other charges, respectively, in our condensed consolidated statements of operations for the nine months ended September 30, 2024. Share Options The grant date fair values of the share options granted in the nine months ended September 30, 2024, were estimated using the Black-Scholes option valuation model, the key assumptions for which are listed in the table below. The expected volatility assumption is based on the historical volatility of a group of ten of our publicly traded peers that operate in the specialty chemical sector. The expected life represents the period of time that options granted are expected to be outstanding. The risk-free interest rate is based on U.S. Treasury securities with terms equal to the expected timing of share option exercises as of the grant date. The dividend yield assumption reflects anticipated dividends on Arcadium's ordinary shares. Arcadium share options granted in the nine months ended September 30, 2024 will vest equally on the first, second and third anniversaries of the grant date and expire ten years from the date of grant. The following summary shows Black Scholes valuation assumptions for Arcadium Plan share options granted in 2024: Nine months ended September 30, 2024 Grant date 3/6/2024 5/14/2024 6/28/2024 7/30/2024 9/1/2024 Expected dividend yield —% —% —% —% —% Expected volatility 31.18% 31.97% 33.00% 33.22% 35.06% Expected life (in years) 6.0 6.0 6.0 6.0 6.0 Risk-free interest rate 4.08% 4.41% 4.28% 4.00% 3.72% The weighted-average grant date fair value of share options granted during the nine months ended September 30, 2024 was $1.89 per share. The following summary shows share option activity for the Allkem Livent Merger and the Arcadium Plan for the nine months ended September 30, 2024: Number of Options Granted But Not Exercised Weighted-Average Remaining Contractual Life Weighted-Average Exercise Price Per Share Aggregate Intrinsic Value (in Millions) Outstanding December 31, 2023 5,060,687 5.6 $ 6.73 $ 6.5 Granted 4,058,953 $ 4.82 Exercised (53,056) $ 4.05 $ — Forfeited (106,548) $ 5.67 Outstanding at September 30, 2024 8,960,036 6.9 $ 5.90 $ 0.1 Exercisable at September 30, 2024 4,118,374 4.3 $ 6.24 $ — As of September 30, 2024, we had total remaining unrecognized compensation cost related to unvested share options of $7.2 million which will be amortized over the weighted-average remaining requisite service period of approximately 2.4 years. Restricted Share Unit Awards The grant date fair value of RSUs under the Arcadium Plan is based on the market price per share of Arcadium's ordinary shares on the date of grant, and the related compensation cost is amortized to expense on a straight-line basis over the vesting period during which the employees perform related services, which for the RSUs granted during the nine months ended September 30, 2024, will vest equally on the first, second and third anniversaries of the grant date. Pursuant to the Allkem Transaction Agreement, on the Acquisition Date, 927,510 employee RSUs vested on an accelerated pro rata basis. The following table shows RSU activity for the Allkem Livent Merger and the Arcadium Plan for the nine months ended September 30, 2024 : Restricted Share Units Number of Weighted-Average Grant Date Fair Value Aggregate Intrinsic Value (in Millions) Nonvested December 31, 2023 2,287,088 $ 7.83 $ 17.1 Granted (1) 5,084,720 $ 4.90 Vested (2) (2,171,932) $ 7.01 Forfeited (164,009) $ 5.62 Nonvested September 30, 2024 5,035,867 $ 5.30 $ 14.4 ___________________ 1. The Company granted 1,080,825 Allkem Replacement Awards on January 12, 2024 pursuant to the Allkem Transaction Agreement. 2. Immediately prior to the Acquisition Date, 768,440 non-employee Director RSUs vested and were paid out in cash of $5.3 million pursuant to the Allkem Transaction Agreement. As of September 30, 2024, the Arcadium Plan had total remaining unrecognized compensation cost related to unvested RSUs of $18.6 million which will be amortized over the weighted-average remaining requisite service period of approximately 2.2 years. Performance-Based Restricted Share Unit ("PRSU") Awards Pursuant to the Allkem Transaction Agreement, on the Acquisition Date, 96,885 employee PRSUs vested on an accelerated basis at the higher of the PRSU payout on the accelerated vest date, which was —%, or 100%. The following table shows PRSU activity for the nine months ended September 30, 2024. Performance-Based Restricted Share Units Number of Weighted-Average Grant Date Fair Value Aggregate Intrinsic Value (in Millions) Nonvested as of December 31, 2023 96,885 $ 9.42 $ 0.7 Vested (96,885) $ 9.42 Nonvested as of September 30, 2024 — $ — $ —

Equity

Equity	9 Months Ended
Equity	Sep. 30, 2024
Equity [Abstract]
Equity	Equity After the closing of the Allkem Livent Merger on January 4, 2024 and as of September 30, 2024, we had 5 billion ordinary shares of $1.00 par value each and 125 million preferred shares of $1.00 par value each authorized. The following is a summary of Arcadium's ordinary shares issued and outstanding: Issued Treasury Outstanding Balance as of December 31, 2023 (1) 433,059,946 (263,669) 432,796,277 Issued to Allkem shareholders - Allkem Livent Merger 641,337,840 — 641,337,840 PRSU and RSU awards accelerated - Allkem Livent Merger 648,969 — 648,969 Arcadium RSU awards 371,750 — 371,750 Arcadium share option awards 8,497 — 8,497 Net sales of treasury shares - Arcadium NQSP — 1,154 1,154 Balance as of September 30, 2024 1,075,427,002 (262,515) 1,075,164,487 _____________________ 1. Balances outstanding as of December 31, 2023, representing predecessor Livent, have been adjusted to reflect the 2.406 Exchange Ratio. Accumulated other comprehensive loss Summarized below is the roll forward of accumulated other comprehensive loss, net of tax. (in Millions) Foreign currency adjustments Derivative Instruments Total Accumulated other comprehensive loss, net of tax as of December 31, 2023 $ (49.8) $ — $ (49.8) Other comprehensive (losses)/income before reclassifications (17.1) 0.2 (16.9) Amounts reclassified from accumulated other comprehensive loss — 0.1 0.1 Accumulated other comprehensive loss, net of tax as of September 30, 2024 $ (66.9) $ 0.3 $ (66.6) (in Millions) Foreign currency adjustments Derivative Instruments Total Accumulated other comprehensive loss, net of tax as of December 31, 2022 $ (51.0) $ — $ (51.0) Other comprehensive income before reclassifications (1.3) — (1.3) Amounts reclassified from accumulated other comprehensive loss — 0.2 0.2 Accumulated other comprehensive loss, net of tax as of September 30, 2023 $ (52.3) $ 0.2 $ (52.1) Dividends

Earnings Per Share

Earnings Per Share	9 Months Ended
Earnings Per Share	Sep. 30, 2024
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share Earnings per ordinary share ("EPS") is computed by dividing net income by the weighted average number of common shares outstanding during the period on a basic and diluted basis. Our potentially dilutive securities include potential ordinary shares related to our share options, restricted share units and 2025 Notes. See Note 12 to our consolidated financial statements in Part II, Item 8 of our 2023 Annual Report on Form 10-K for more information. Diluted earnings per share ("Diluted EPS") considers the impact of potentially dilutive securities except in periods in which there is a loss because the inclusion of the potential ordinary shares would have an anti-dilutive effect. Diluted EPS excludes the impact of potential ordinary shares related to our share options in periods in which the option exercise price is greater than the average market price of our ordinary shares for the period. We use the if-converted method when calculating the potential dilutive effect, if any, of our 2025 Notes. Earnings applicable to ordinary shares and ordinary shares used in the calculation of basic and diluted earnings per share are as follows: (in Millions, Except Share and Per Share Data) Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 (1) 2024 2023 (1) Numerator: Net income attributable to Arcadium Lithium plc $ 16.1 $ 87.4 $ 117.4 $ 292.4 Denominator: Weighted average ordinary shares outstanding - basic 1,075.1 432.4 1,067.8 432.3 Dilutive share equivalents from share-based plans 0.8 3.5 0.9 3.5 Dilutive share equivalents from 2025 Notes 67.7 67.7 67.7 67.7 Weighted average ordinary shares outstanding - diluted 1,143.6 503.6 1,136.4 503.5 Basic earnings per ordinary share $ 0.01 $ 0.20 $ 0.11 $ 0.68 Diluted earnings per ordinary share $ 0.01 $ 0.17 $ 0.10 $ 0.58 _____________________ 1. For the three and nine months ended September 30, 2023, weighted average ordinary shares outstanding - basic and diluted, dilutive share equivalents and basic and diluted earnings per ordinary share amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Anti-dilutive share options For the three months ended September 30, 2024, options to purchase 9,163,458 shares of our ordinary shares, at an average exercise price of $5.90 per share, were anti-dilutive and not included in the computation of diluted earnings per share because the exercise price of the options was greater than the average market price of the ordinary shares for the period. For the nine months ended September 30, 2024, options to purchase 8,211,667 shares of our ordinary shares, at an average exercise price of $6.19 per share, were anti-dilutive and not included in the computation of diluted earnings per share because the exercise price of the options was greater than the average market price of the ordinary shares for the period. For the three months ended September 30, 2023, options to purchase 435,544 shares of our ordinary shares, at an average exercise price of $9.70 per share were anti-dilutive and not included in the computation of diluted earnings per share because the exercise price of the options was greater than the average market price of the ordinary shares for the period. For the nine months ended September 30, 2023, options to purchase 353,128 shares of our ordinary shares, at an average exercise price of $9.70 per share were anti-dilutive and not included in the computation of diluted earnings per share because the exercise price of the options was greater than the average market price of the ordinary shares for the period.

Financial Instruments, Risk Man

Financial Instruments, Risk Management and Fair Value Measurements	9 Months Ended
	Sep. 30, 2024
Fair Value Disclosures [Abstract]
Financial Instruments, Risk Management and Fair Value Measurements	Financial Instruments, Risk Management and Fair Value Measurements Our financial instruments include cash and cash equivalents, trade receivables, other current assets, investments held in trust fund, trade payables, derivatives and amounts included in accruals meeting the definition of financial instruments. Investments in the Arcadium NQSP deferred compensation plan trust fund are considered Level 1 investments based on readily available quoted prices in active markets for identical assets. The carrying value of cash and cash equivalents, trade receivables, other current assets, and trade payables approximates their fair value due to their short-term nature and are considered Level 1 investments. Our other financial instruments include the following: Financial Instrument Valuation Method Foreign exchange forward contracts Estimated amounts that would be received or paid to terminate the contracts at the reporting date based on current market prices for applicable currencies. The estimated fair value of our foreign exchange forward contracts has been determined using standard pricing models which take into account the present value of expected future cash flows discounted to the balance sheet date. These standard pricing models utilize inputs derived from, or corroborated by, observable market data such as currency and commodity spot and forward rates. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). The inputs used to measure fair value are classified into the following hierarchy: Level 1 - Unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 - Unadjusted quoted prices in active markets for similar assets or liabilities, or unadjusted quoted prices for identical or similar assets or liabilities in markets that are not active, or inputs other than quoted prices that are observable for the asset or liability. Level 3 - Unobservable inputs for the asset or liability. The estimated fair value and the carrying amount of debt were $772.9 million and $724.4 million, respectively, as of September 30, 2024. Our 2025 Notes are classified as Level 2 in the fair value hierarchy. Use of Derivative Financial Instruments to Manage Risk We mitigate certain financial exposures connected to currency risk through a program of risk management that includes the use of derivative financial instruments. We enter into foreign exchange forward contracts to reduce the effects of fluctuating foreign currency exchange rates. We formally document all relationships between hedging instruments and hedged items, as well as the risk management objective and strategy for undertaking various hedge transactions. This process includes relating derivatives that are designated as fair value or cash flow hedges to specific assets and liabilities on the balance sheet or to specific firm commitments or forecasted transactions. We also assess both at the inception of the hedge and on an ongoing basis, whether each derivative is highly effective in offsetting changes in fair values or cash flows of the hedged item. If we determine that a derivative is not highly effective as a hedge, or if a derivative ceases to be a highly effective hedge, we discontinue hedge accounting with respect to that derivative prospectively. Foreign Currency Exchange Risk Management We conduct business in many foreign countries, exposing earnings, cash flows, and our financial position to foreign currency risks. The majority of these risks arise as a result of foreign currency transactions. The primary currencies for which we have exchange rate exposure are the Euro, the British pound, the Chinese yuan, the Argentine peso, the Australian dollar, the Canadian dollar and the Japanese yen. We currently do not hedge foreign currency risks associated with the Argentine peso due to the limited availability and the high cost of suitable derivative instruments. Our policy is to minimize exposure to adverse changes in currency exchange rates. This is accomplished through a controlled program of risk management that could include the use of foreign currency debt and forward foreign exchange contracts. We also use forward foreign exchange contracts to hedge firm and highly anticipated foreign currency cash flows, with an objective of balancing currency risk to provide adequate protection from significant fluctuations in the currency markets. Concentration of Credit Risk Our counterparties to derivative contracts are primarily major financial institutions. We limit the dollar amount of contracts entered into with any one financial institution and monitor counterparties’ credit ratings. We also enter into master netting agreements with each financial institution, where possible, which helps mitigate the credit risk associated with our financial instruments. While we may be exposed to credit losses due to the nonperformance of counterparties, we consider this risk remote. Accounting for Derivative Instruments and Hedging Activities Cash Flow Hedges We recognize all derivatives on the balance sheet at fair value. On the date we enter into the derivative instrument, we generally designate the derivative as a hedge of the variability of cash flows to be received or paid related to a forecasted transaction (cash flow hedge). We record in accumulated other comprehensive loss ("AOCL") changes in the fair value of derivatives that are designated as and meet all the required criteria for, a cash flow hedge. We then reclassify these amounts into earnings as the underlying hedged item affects earnings. In contrast, we immediately record in earnings changes in the fair value of derivatives that are not designated as cash flow hedges. As of September 30, 2024, we had open foreign currency forward contracts in AOCL in a net after-tax gain position of $0.3 million designated as cash flow hedges of underlying forecasted sales and purchases. As of September 30, 2024, we had open forward contracts with various expiration dates to buy, sell or exchange foreign currencies with a U.S. dollar equivalent of approximately $10.7 million. A net after-tax gain of $0.3 million, representing open foreign currency exchange contracts, will be realized in earnings during the year ending December 31, 2024 if spot rates in the future are consistent with market rates as of September 30, 2024. The actual effect on earnings will be dependent on the actual spot rates when the forecasted transactions occur. We recognize derivative gains and losses in the Cost of sales line in the condensed consolidated statements of operations. Derivatives Not Designated As Cash Flow Hedging Instruments We hold certain forward contracts that have not been designated as cash flow hedging instruments for accounting purposes. Contracts used to hedge the exposure to foreign currency fluctuations associated with certain monetary assets and liabilities are not designated as cash flow hedging instruments and changes in the fair value of these items are recorded in earnings. We had open forward contracts not designated as cash flow hedging instruments for accounting purposes with various expiration dates to buy, sell or exchange foreign currencies with a U.S. dollar equivalent of approximately $115.1 million as of September 30, 2024. Fair Value of Derivative Instruments The following table provides the gross fair value and net balance sheet presentation of our derivative instruments. The Company had no open derivative cash flow hedge contracts as of December 31, 2023. September 30, 2024 Gross Amount of Derivatives (in Millions) Designated as Cash Flow Hedges Derivative assets Foreign exchange contracts $ 0.4 Total derivative assets (1) 0.4 Net derivative assets $ 0.4 __________________ 1. Net balance is included in Prepaid and other current assets in the condensed consolidated balance sheets. The following tables summarize the gains or losses related to our cash flow hedges and derivatives not designated as cash flow hedging instruments. Derivatives in Cash Flow Hedging Relationships (in Millions) Total Foreign Exchange Contracts Accumulated other comprehensive income, net of tax as of December 31, 2023 $ — Unrealized hedging gains, net of tax 0.2 Total derivatives instruments impact on comprehensive income, net of tax 0.2 Accumulated other comprehensive income, net of tax as of March 31, 2024 $ 0.2 Unrealized hedging gains, net of tax 0.1 Total derivatives instruments impact on comprehensive income, net of tax 0.1 Accumulated other comprehensive income, net of tax at June 30, 2024 $ 0.3 Unrealized hedging losses, net of tax (0.1) Reclassification of deferred hedging losses, net of tax 0.1 Total derivatives instruments impact on comprehensive income, net of tax — Accumulated other comprehensive income, net of tax at September 30, 2024 $ 0.3 (in Millions) Total Foreign Exchange Contracts Accumulated other comprehensive income, net of tax as of December 31, 2022 $ — Unrealized hedging gains, net of tax 0.2 Total derivatives instruments impact on comprehensive income, net of tax 0.2 Accumulated other comprehensive income, net of tax as of March 31, 2023 $ 0.2 Unrealized hedging gains, net of tax 0.4 Total derivatives instruments impact on comprehensive income, net of tax 0.4 Accumulated other comprehensive income, net of tax at June 30, 2023 $ 0.6 Unrealized hedging losses, net of tax (0.6) Reclassification of deferred hedging gains, net of tax 0.2 Total derivatives instruments impact on comprehensive income, net of tax (0.4) Accumulated other comprehensive income, net of tax at September 30, 2023 $ 0.2 Derivatives Not Designated as Cash Flow Hedging Instruments Location of Gain or (Loss) Amount of Pre-tax Gain or (Loss) Recognized in Income on Derivatives (1) Three Months Ended September 30, Nine Months Ended September 30, (in Millions) 2024 2023 2024 2023 Foreign Exchange contracts Other gain/(loss) $ 2.2 $ (0.1) $ 15.3 $ 1.8 Total $ 2.2 $ (0.1) $ 15.3 $ 1.8 ____________________ 1. Amounts represent the gain or loss on the derivative instrument offset by the gain or loss on the hedged item. Fair Value Measurements Recurring Fair Value Measurements The following tables present our fair-value hierarchy for those assets and liabilities measured at fair-value on a recurring basis in our condensed consolidated balance sheets. (in Millions) September 30, 2024 Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Assets Investments in deferred compensation plan (1) $ 6.9 $ 6.9 $ — $ — JEMSE Receivable 5.0 — — 5.0 Equity securities (2) 0.7 0.7 — — Derivatives – Foreign exchange 0.4 — 0.4 — Total Assets $ 13.0 $ 7.6 $ 0.4 $ 5.0 Liabilities Deferred compensation plan obligation (3) $ 7.6 $ 7.6 $ — $ — Total Liabilities $ 7.6 $ 7.6 $ — $ — (in Millions) December 31, 2023 Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Assets Investments in deferred compensation plan (1) $ 4.1 $ 4.1 $ — — Total Assets $ 4.1 $ 4.1 $ — $ — Liabilities Deferred compensation plan obligation (3) $ 6.7 $ 6.7 $ — $ — Total Liabilities (4) $ 6.7 $ 6.7 $ — $ — ____________________ 1. Balance is included in Investments in the condensed consolidated balance sheets. Arcadium NQSP investments in Arcadium ordinary shares are recorded as Treasury shares in the condensed consolidated balance sheets and carried at historical cost. Mark-to-market gains of $0.1 million and $1.2 million were recorded for the three and nine months ended September 30, 2024, respectively. Mark-to-market gains of $1.0 million and $0.2 million were recorded for the three and nine months ended September 30, 2023, related to the Arcadium ordinary shares. The mark-to-market gains and losses were recorded in Selling, general and administrative expenses in the condensed consolidated statements of operations, with a corresponding offset to the deferred compensation plan obligation in the condensed consolidated balance sheets. 2. Mark-to-market gains and losses are recorded to Other gain/loss in the condensed consolidated statement of operations. 3. Balance is included in Other long-term liabilities in the condensed consolidated balance sheets. 4.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
Commitments and Contingencies	Sep. 30, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Contingencies We are a party to various legal proceedings, certain of these matters are discussed below. Arcadium records liabilities for estimated losses from contingencies when information available indicates that a loss is probable and the amount of the loss, or range of loss, can be reasonably estimated. As additional information becomes available, management adjusts its assessments and estimates. Legal costs are expensed as incurred. In addition to the legal proceedings noted below, we have certain contingent liabilities arising in the ordinary course of business. Some of these contingencies are known but are so preliminary that the merits cannot be determined, or if more advanced, are not deemed material based on current knowledge; and some are unknown - for example, claims with respect to which we have no notice or claims which may arise in the future from products sold, guarantees or warranties made, or indemnities provided. Therefore, we are unable to develop a reasonable estimate of our potential exposure of loss for these contingencies, either individually or in the aggregate, at this time. There can be no assurance that the outcome of these contingencies will be favorable, and adverse results in certain of these contingencies could have a material adverse effect on the consolidated financial position, results of operations in any one reporting period, or liquidity. Argentine Customs & Tax Authority Matters Minera del Altiplano SA, our subsidiary in Argentina ("MdA"), has received notices from the Argentine Customs Authorities that they are conducting customs audits in Salta (for 2015 to 2019, 2021 and 2022), Rosario (for 2016 and 2017), Buenos Aires and Ezeiza (for 2018, 2019, 2021 and 2022) regarding the export of lithium carbonate by MdA from each of those locations. See Note 21 for more information about the payment the Company made in June 2023 for export duties and interest claimed by the Customs Authorities of Buenos Aires, Ezeiza and Salta related to exports made between the years 2018 – 2022. Sales de Jujuy S.A., our subsidiary in Argentina ("SDJ") has received a notice from the Argentine Customs Authority regarding custom duties for the export of lithium carbonate by SDJ from January 2022 through August 2023. SDJ also received notification from Jujuy provincial tax authority regarding a royalty adjustment in favor of the Province for the periods 2021 and 2022. A range of reasonably possible liabilities, if any, cannot be currently estimated by the Company. MdA was also notified from the Argentine Tax Authority of the start of transfer pricing audits for the periods 2017 and 2018. SDJ was also notified by the Argentine Tax Authority of the start of a transfer pricing audit for the period of 2018. In January, 2023, the Argentina Ministry of Economy issued a resolution to cancel an export rebate regime relating to lithium products, which was followed by Presidential Decree No. 57/2023 in February, 2023. The Presidential Decree prospectively cancels all export rebates for lithium products. Prior to the Presidential Decree, MdA and SDJ had the right to collect 4% of the FOB value for exported products (which consisted of the "La Puna" rebate which was 2.5% and the "Export" rebate which was 1.5%). In October 2023 by Presidential Decree No. 557/2023 the Export rebate of 1.5% was reinstated. Subsequent to the Presidential Decree entering into force on October 26, 2023 MdA and SDJ are entitled to the 1.5% rebate/refund on FOB value of its exported products. As of September 30, 2024, MdA and SDJ have a receivable of approximately $5.1 million USD and $1.5 million USD, respectively, which is still valid and remains in force after the Presidential Decrees. A range of possible liabilities, if any, cannot be currently estimated by the Company. Australia Tax Matters We were informed on April 16, 2024 that the Australian Taxation Office will be performing a combined assurance review of Allkem Pty Ltd and its Australian subsidiaries for the period of July 1, 2019 to June 30, 2023. Canada Tax Matters We were notified that Nemaska Lithium has received certain audit queries from the Canada Revenue Agency ("CRA") related to the Approval and Vesting Order (the "RVO") issued under the Companies' Creditors Arrangement Act ("CCAA") on October 15, 2020, by the Superior Court of Québec. Nemaska Lithium has been responding to those queries. Securities Class Action Lawsuits On September 6, 2024, two separate securities class action lawsuits were filed against the Company in the Court of Common Pleas of Philadelphia County, Pennsylvania (City of Pontiac Reestablished General Employees’ Retirement System, on behalf of itself and all others similarly situated vs. Arcadium Lithium plc et. al., and Satish Chalasani and Kelly Johnson, individually and on behalf of all others similarly situated vs. Arcadium Lithium plc et. al.). Each lawsuit is alleging securities law claims arising from the Allkem Livent Merger and is seeking unspecified monetary damages. A range of possible liabilities, if any, cannot be currently estimated by the Company. Leases All of our leases are operating leases as of September 30, 2024 and December 31, 2023. We have operating leases for corporate offices, manufacturing facilities, and land. Our leases have remaining lease terms of two The Company assumed an ROU asset and corresponding lease liability of $53.4 million in the Allkem Livent Merger, all of which are accounted for as operating leases. Quantitative disclosures about our leases are summarized in the table below. Three Months Ended September 30, Nine Months Ended September 30, (in Millions, except for weighted-average amounts) 2024 2023 2024 2023 Lease Cost Operating lease cost $ 4.4 $ 0.4 $ 12.9 $ 1.0 Short-term lease cost 0.1 0.1 0.3 0.3 Total lease cost (1) $ 4.5 $ 0.5 $ 13.2 $ 1.3 Other information Cash paid for amounts included in the measurement of lease liabilities: Cash paid for operating leases $ 4.2 $ 0.4 $ 12.4 $ 1.1 __________________________ 1. Lease expense is classified as Selling, general and administrative expenses in our condensed consolidated statements of operations. As of September 30, 2024, our operating leases had a weighted average remaining lease term of 8.4 years and a weighted average discount rate of 8.6%. The table below presents a maturity analysis of our operating lease liabilities for each of the next five years and a total of the amounts for the remaining years. (in Millions) Undiscounted cash flows Remainder of 2024 $ 3.1 2025 10.3 2026 9.5 2027 8.8 2028 8.5 Thereafter 35.6 Total future minimum lease payments 75.8 Less: Imputed interest (19.3) Total $ 56.5

Supplemental Information

Supplemental Information	9 Months Ended
Supplemental Information	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Supplemental Information	Supplemental Information The following tables present details of prepaid and other current assets, other assets, accrued and other current liabilities, and other long-term liabilities as presented on the condensed consolidated balance sheets: (in Millions) September 30, 2024 December 31, 2023 Prepaid and other current assets Tax related items $ 100.8 $ 29.5 Prepaid expenses 51.0 16.9 Argentina government receivable (1) 42.2 7.9 Other receivables 48.4 28.2 Bank Acceptance Drafts (2) 1.7 — Derivative assets (Note 19) 0.4 — Other current assets 3.4 3.9 Total $ 247.9 $ 86.4 (in Millions) September 30, 2024 December 31, 2023 Other assets Argentina government receivable (1), (3) $ 119.6 $ 71.3 Advance to contract manufacturers (4) 27.4 27.6 Long-term semi-finished goods inventory 142.4 1.0 Tax related items 4.3 4.0 Capitalized software, net 1.8 1.1 Investment in transit - Nemaska Lithium (5) 43.9 — Other assets 50.0 22.7 Total $ 389.4 $ 127.7 _________________ 1. We have various subsidiaries that conduct business in Argentina. As of September 30, 2024 and December 31, 2023, $41.5 million and $38.8 million, respectively, of outstanding receivables due from the Argentina government, which primarily represent export tax and export rebate receivables, was denominated in U.S. dollars. A recent judicial decision relating to the U.S. dollar-denominated export tax receivable portion of $34.8 million permits the Argentina government to reimburse us in Argentine pesos at the historical foreign exchange rate applicable at each past payment date, adjusted by a bank deposit interest rate. While Arcadium filed an appeal on November 6, 2023 and believes it has valid defenses on the technical merits, the ultimate resolution of this matter could result in a possible loss of up to $34.3 million. We continually review the recoverability of all outstanding receivables by analyzing historical experience, current collection trends and regional business and political factors among other factors. 2. Bank Acceptance Drafts are a common Chinese finance note used to settle trade transactions. The Company accepts these notes from Chinese customers based on criteria intended to ensure collectability and limit working capital usage. 3. In June 2023, the Company decided to pay $21.7 million for the export duties and interest claimed by the Customs Authorities of Buenos Aires, Ezeiza and Salta related to exports made between the years 2018 – 2022 registered in those locations. This payment stops the accrual of any further interest. It was a deposit made under protest and was not an admission of any of the claims made by the Customs Authorities or a waiver of any of the Company's defenses, including recovery of the deposit plus interest. The cases remain in discussion. See Note 20 for more information. 4. We record deferred charges for certain contract manufacturing agreements which we amortize over the term of the underlying contract. 5. Represents the Company's cash contributed to Nemaska Lithium in the third quarter of 2024 which, due to one-quarter lag reporting, are not yet recorded in our consolidation of Nemaska. The balance is recorded to Other assets - noncurrent because the cash is expected to be used by Nemaska primarily for capital expenditures. IQ contemporaneously made an equal contribution in the third quarter of 2024 which, due to one-quarter lag reporting, is not recorded in our consolidation of Nemaska. See Note 9 for details. (in Millions) September 30, 2024 December 31, 2023 Accrued and other current liabilities Accrued payroll $ 55.5 $ 31.2 Restructuring reserves 2.0 1.7 Retirement liability - 401k 3.6 3.2 Environmental reserves, current 2.8 0.5 Accrued investment in unconsolidated affiliates — 27.0 Other accrued and other current liabilities (1) 111.6 73.2 Total $ 175.5 $ 136.8 (in Millions) September 30, 2024 December 31, 2023 Other long-term liabilities Deferred compensation plan obligation $ 7.6 $ 6.7 Contingencies related to uncertain tax positions (2) 9.1 6.2 Self-insurance reserves 1.1 1.1 Asset retirement obligations 12.5 3.7 Other long-term liabilities 61.7 3.6 Total $ 92.0 $ 21.3 ____________________ 1. Amounts p rimarily include accrued capital expenditures related to our expansion projects. 2. As of September 30, 2024, we have recorded a liability for uncertain tax positions of $8.7 million and a $0.4 million indemnification liability where the offsetting uncertain tax position is with FMC, per the tax matters agreement.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023		Sep. 30, 2024	Sep. 30, 2023
Pay vs Performance Disclosure
Net income attributable to Arcadium Lithium plc	$ 16.1	$ 87.4	[1]	$ 117.4	$ 292.4	[1]

[1] For the three and nine months ended September 30, 2023, basic and diluted earnings per ordinary share and weighted average ordinary shares outstanding - basic and diluted amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Represents the results of predecessor Livent’s operations for three and nine months ended September 30, 2023 which do not include the operations of Allkem.

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Sep. 30, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Significant Accounting Polici_2

Significant Accounting Policies and Related Financial Information (Policies)	9 Months Ended
	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Principal Accounting Policies and Related Financial Information	The accompanying condensed consolidated financial statements were prepared in accordance with the requirements of the Securities and Exchange Commission ("SEC") for interim reporting. As permitted under those rules, certain notes or other financial information that are normally required by U.S. GAAP have been condensed or omitted from these interim financial statements.
Reclassifications	Reclassifications Certain prior period balances have been reclassified to conform to the current period presentation in the condensed consolidated financial statements and the accompanying notes.
Segment Information	Segment Information
Revenue Recognition	Revenue Recognition Revenue from product sales is recognized when we satisfy a performance obligation by transferring the promised goods to a customer, that is, when control of the good transfers to the customer. Payment terms generally range from 20 to 180 days. In determining when the control of goods is transferred, we typically assess, among other things, the transfer of title and risk of loss and the shipping terms of the contract. We record amounts billed for shipping and handling fees as revenue. Costs incurred for shipping and handling are recorded in cost of sales. When we perform shipping and handling activities after the transfer of control to the customer (e.g., when control transfers prior to delivery), they are considered fulfillment activities, and accordingly, the costs are accrued to cost of sales when the related revenue is recognized. Amounts billed for sales and use taxes, VAT, and certain excise and other specific transactional taxes imposed on revenue-producing transactions are presented on a net basis and excluded from revenue in the condensed consolidated statements of operations. We record a liability until remitted to the respective taxing authority. We satisfy our obligations by transferring goods and services in exchange for consideration from customers. The timing of performance sometimes differs from the timing the associated consideration is received from the customer, thus resulting in the recognition of a contract asset or liability. These may arise from provisional pricing within certain of our customer contracts, or if the customer’s payment of consideration is received prior to completion of our related performance obligation. Provisional pricing results in variable consideration which we estimate by using an expected value method taking into account all information that is reasonably available including publicly available pricing forecasts. We only include variable consideration within the transaction price to the extent that it is probable that a significant reversal in the amount of revenue recognized will not occur. Performance obligations
Equity method investments	Equity method investments We stop applying the equity method when we have reduced the value of our equity method investment, commitments and additional investments (i.e., loans or advances) in the investee to zero. If the investee subsequently reports net income, we resume applying the equity method when our share of that net income is equal to the suspended losses (i.e., our share of the investee's net losses not previously recognized).
Goodwill	Goodwill The Company accounts for goodwill and other intangibles acquired in a business combination in conformity with current accounting guidance that requires that goodwill and indefinite-lived intangible assets not be amortized. Under the guidance, goodwill is tested for impairment by comparing the estimated fair value of reporting units to the related carrying value. Reporting units are either operating business segments or one level below operating business segments for which discrete financial information is available and for which operating results are regularly reviewed by the business management. In applying the goodwill impairment test, a qualitative test ("Step 0") is initially performed, under which qualitative factors are assessed to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying value. Qualitative factors may include, but are not limited to, economic conditions, industry and market considerations, cost factors, overall financial performance of the reporting units and other entity and reporting unit specific events. If after assessing these qualitative factors, it is determined that it is "more-likely-than-not" that the fair value of the reporting unit is less than the carrying value, a quantitative test ("Step 1") is performed. During Step 1, the fair value is estimated using a discounted cash flow model. Impairment evaluations of goodwill could result in a reduction in our recorded asset values which could have a material adverse effect on our financial position and results of operations. We perform reviews of goodwill on an annual basis, or more frequently if triggering events indicate a possible impairment. We test goodwill at the reporting unit level by comparing the carrying value of the net assets of the reporting unit, including goodwill, to the reporting unit's fair value. If the carrying values of goodwill exceed their fair value, the goodwill would be considered impaired. If any impairment or related charge is warranted, our financial position and results of operations could be materially affected. Any such impairment or related charge could be a result of, for example, sustained declines in the Company’s stock price; the deterioration of the cost of equity or debt capital increases due to valuations for comparable companies or comparable acquisitions valuations; or the deterioration of the outlook for future cash flows for the reporting unit due to but not limited to, increased competition, changes to discount rate, downward forecast revisions, restricted plans or changes in applicable regulations affecting our business.
Mine Development Costs and Mineral Interests	Mine Development Costs Mine development costs include: a) exploration and evaluation ("E&E") expenditures incurred during the search for mineral resources as well as the determination of the technical feasibility and commercial viability of extracting the mineral resource; and b) stripping costs of removing overburden and waste materials to access the mineral body at an open pit mine. The Company capitalizes E&E expenditures to Property, Pland and Equipment ("PP&E") under a successful efforts basis when proven and probable reserves are established for the sites where E&E activities are being performed. E&E assets recognized as part of business combinations are also capitalized. All other E&E expenditures are expensed. Stripping costs incurred prior to the production phase are capitalized to PP&E during the development of an open pit mine. When multiple open pits exist at a mining complex utilizing common processing facilities, such pre-production stripping costs are capitalized at each pit. The removal, production, and sale of de minimis saleable materials may occur during the development phase of an open pit mine and are assigned incremental mining costs related to the removal of that material. The production phase of an open pit mine commences when saleable minerals, beyond a de minimis amount, are produced. Stripping costs incurred during the production phase of a mine are variable production costs that are included as a component of inventory to be recognized in Cost of sales in the same period as the revenue from sale of that inventory. Capitalized mine development costs are amortized using the units-of-production method based on estimated recoverable minerals in proven and probable reserves, and are amortized over the estimated life of the mineral body. Mineral Interests Mineral interests include acquired interests in production, development and exploration stage properties. Mineral interests are capitalized at their fair value at the acquisition date, either as an individual asset purchase or as part of a business combination. Mineral interests in the development and exploration stage are not amortized until the underlying property is converted to the production stage, at which point the mineral interests are amortized over the estimated recoverable proven and probable reserves using a units-of-production method.
Asset Retirement Obligations	Asset Retirement Obligations
Recently Issued and Adopted Accounting Pronouncements and Regulatory Items	In December 2023, the Financial Accounting Standard Board ("FASB") issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures . This ASU enhances existing income tax disclosures to better assess how an entity's operation and related tax risks, tax planning, and operational opportunities affect its tax rate and prospects for future cash flows. The ASU is effective for annual periods beginning after December 15, 2024. We are currently evaluating the effect the guidance will have on our condensed consolidated financial statements. In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures . This ASU improves reportable segment disclosure requirements, primarily through enhanced disclosures related to significant segment expenses. The ASU is effective for annual periods beginning after December 15, 2023, and interim periods beginning after December 15, 2024. We are currently evaluating the effect the guidance will have on our condensed consolidated financial statements.

Significant Accounting Polici_3

Significant Accounting Policies and Related Financial Information (Tables)	9 Months Ended
	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Impact of Reclassifications	The following tables summarize the accounts that were recast for the three and nine months ended September 30, 2023 and the three months ended March 31, 2024 to conform to the current period presentation. Three Months Ended September 30, Nine Months Ended September 30, 2023 2023 (in Millions) Prior Presentation Loss/(gain) Reclassified Recast Presentation Prior Presentation Loss/(gain) Reclassified Recast Presentation Cost of sales $ 94.9 $ 11.3 $ 83.6 $ 274.8 $ 16.4 $ 258.4 Restructuring and other charges 8.6 (0.1) 8.7 34.7 (0.3) 35.0 Other (gains)/losses (10.0) 11.2 1.2 (21.4) 16.1 (5.3) Three Months Ended March 31, 2024 (in Millions) Prior Presentation (Gain)/loss Reclassified Recast Presentation Cost of sales $ 116.8 $ (38.0) $ 154.8 Restructuring and other charges 83.6 3.8 79.8 Other (gains)/losses (43.1) (34.2) (77.3)

Allkem Livent Merger (Tables)

Allkem Livent Merger (Tables)	9 Months Ended
Allkem Livent Merger (Tables)	Sep. 30, 2024
Business Combination, Asset Acquisition, and Joint Venture Formation [Abstract]
Schedule of Consideration Transferred	The Acquisition Date fair value of consideration transferred consisted of the following: (in millions) Amount Consideration: Fair value of Arcadium ordinary shares issued to Allkem shareholders $ 4,385.6 Fair value of converted Allkem performance rights attributable to pre-combination service 4.8 Total consideration $ 4,390.4
Schedule of Purchase Price Allocation	The following table summarizes the preliminary purchase price allocation for the Allkem Livent Merger as of January 4, 2024, which is subject to change: (in Millions, except per share amounts) Amount Total consideration $ 4,390.4 Assets acquired: Cash and cash equivalents $ 681.4 Trade receivables 64.2 Inventories 121.3 Prepaid and other current assets 87.2 Property, plant and equipment 4,326.1 Right of use assets - operating leases, net 53.4 Deferred income tax assets 9.6 Other assets (1) 192.7 Total assets acquired $ 5,535.9 Liabilities assumed: Accounts payable, trade and other $ 223.7 Accrued and other current liabilities 35.1 Income taxes 78.5 Long-term debt including current portion 301.7 Operating lease liabilities - long-term 53.4 Environmental liabilities 9.8 Deferred income tax liabilities 1,289.0 Other long-term liabilities 53.2 Total liabilities assumed $ 2,044.4 Fair value of net assets acquired $ 3,491.5 Add: Fair value of noncontrolling interests acquired 275.0 Fair value of net assets acquired less noncontrolling interests acquired $ 3,216.5 Goodwill $ 1,173.9 ___________________ 1. Includes long-term semi-finished goods inventory.
Schedule of Pro Forma Information	The following table represents Allkem's revenues and net earnings included in Arcadium's condensed consolidated statements of operations from the Acquisition Date through September 30, 2024. (in Millions) Three Months Ended September 30, Nine Months Ended September 30, 2024 Revenue $ 56.6 $ 242.9 (Loss)/income from operations before income taxes $ (44.6) $ 107.6 (in Millions) Three Months Ended September 30, Nine Months Ended September 30, 2023 (Unaudited) Revenue $ 538.5 $ 1,677.7 Net income 299.0 $ 812.4

Goodwill (Tables)

Goodwill (Tables)	9 Months Ended
Goodwill (Tables)	Sep. 30, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The following table summarizes the changes in goodwill for the nine months ended September 30, 2024 . (in Millions) Allkem Nemaska Lithium Total Balance as of December 31, 2023 $ — $ 120.7 $ 120.7 Acquisitions - Allkem Livent Merger 1,189.2 — 1,189.2 Measurement period adjustments (15.3) (1.4) (16.7) Balance as of September 30, 2024 $ 1,173.9 $ 119.3 $ 1,293.2 See Note 4 for further details.

Revenue Recognition (Tables)

Revenue Recognition (Tables)	9 Months Ended
Revenue Recognition (Tables)	Sep. 30, 2024
Revenue from Contract with Customer [Abstract]
Schedule of Disaggregation of Revenue	The following table provides information about disaggregated revenue by major geographical region: (in Millions) Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Asia Pacific (1) $ 172.4 $ 163.8 $ 604.3 $ 502.4 North America (1) 22.1 31.9 65.6 124.5 Europe, Middle East & Africa 8.6 15.6 47.6 72.0 Latin America — 0.1 1.3 1.8 Consolidated Revenue $ 203.1 $ 211.4 $ 718.8 $ 700.7 1. During the three months ended September 30, 2024, countries with sales in excess of 10% of consolidated revenue consisted of China, Japan, South Korea and United States. Sales for the three months ended September 30, 2024 for China, Japan, South Korea and United States totaled $111.4 million, $33.9 million, $24.8 million, and $21.7 million, respectively. During the nine months ended September 30, 2024, countries with sales in excess of 10% of consolidated revenue consisted of China, Japan, and South Korea. Sales for the nine months ended September 30, 2024 for China, Japan, and South Korea totaled $392.4 million, $111.7 million, and $89.8 million, respectively. During the three months ended September 30, 2023, countries with sales in excess of 10% of consolidated revenue consisted of China, Japan, the United States, and South Korea. Sales for the three months ended September 30, 2023 for China, Japan, the United States, and South Korea totaled $95.6 million, $42.1 million, $30.0 million, and $20.6 million, respectively. During the nine months ended September 30, 2023, countries with sales in excess of 10% of consolidated revenue consisted of China, the United States, Japan, and South Korea. Sales for the nine months ended September 30, 2023 for China, the United States, Japan, and South Korea, totaled $274.9 million, $120.0 million, $118.2 million, and $86.9 million, respectively. The following table provides information about disaggregated revenue by major product category: (in Millions) Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Lithium Hydroxide $ 85.6 $ 142.8 $ 309.3 $ 449.2 Lithium Carbonate (1) 56.0 9.0 208.5 23.6 Butyllithium and Other Lithium Specialties 39.4 59.6 130.2 227.9 Spodumene Concentrate (2) 22.1 — 70.8 — Consolidated Revenue $ 203.1 $ 211.4 $ 718.8 $ 700.7 ______________________ 1. Includes lithium carbonate by-product revenue. 2. Includes low-grade spodumene sales and minimal other products.
Schedule of Receivables and Contract Liabilities	The following table presents the opening and closing balances of our contract liabilities and current trade receivables, net of allowances from contracts with customers. (in Millions) Balance as of September 30, 2024 Balance as of December 31, 2023 (Decrease)/increase Receivables from contracts with customers, net of allowances $ 90.2 $ 106.7 $ (16.5) Contract liability - short-term 55.1 4.4 50.7 Contract liability - long-term 251.2 217.8 33.4

Inventories, Net (Tables)

Inventories, Net (Tables)	9 Months Ended
Inventories, Net (Tables)	Sep. 30, 2024
Inventory Disclosure [Abstract]
Schedule of Inventories	Inventories consisted of the following: (in Millions) September 30, 2024 December 31, 2023 Finished goods $ 139.9 $ 59.1 Semi-finished goods 143.6 108.8 Raw materials, supplies, and other 106.1 49.6 Inventory, net $ 389.6 $ 217.5

Investments (Tables)

Investments (Tables)	9 Months Ended
Investments (Tables)	Sep. 30, 2024
Equity Method Investments and Joint Ventures [Abstract]
Schedule of Investments in and Advances to Affiliates, Schedule of Investments	Investments consisted of the following: (in Millions) September 30, 2024 December 31, 2023 ESM ILiAD, LLC $ 30.1 $ 30.1 Arcadium NQSP 6.8 4.7 TLC (Naraha plant) 2.4 — Other 0.7 — Investments $ 40.0 $ 34.8

Property, Plant and Equipment_2

Property, Plant and Equipment, Net (Tables)	9 Months Ended
Property, Plant and Equipment, Net (Tables)	Sep. 30, 2024
Property, Plant and Equipment [Abstract]
Schedule of Property, Plant and Equipment	Property, plant and equipment consisted of the following: (in Millions) September 30, 2024 December 31, 2023 Land and land improvements $ 334.7 $ 106.2 Buildings 985.3 134.9 Machinery and equipment 985.6 420.7 Mineral rights 3,279.6 560.0 Construction in progress 2,009.5 1,284.4 Total cost $ 7,594.7 $ 2,506.2 Accumulated depreciation (345.5) (269.1) Property, plant and equipment, net $ 7,249.2 $ 2,237.1 Asset type Depreciation and amortization method Useful Life Land N/A — Land improvements Straight-line 20 years Buildings Straight-line 20-40 years Mineral rights Units-of-production Based on rate of depletion of reserves Mining extraction equipment Units-of-production Based on rate of depletion of reserves Leased plant and equipment Straight-line Lease period (1-10.5 years) Other machinery and equipment Straight-line 3-18 years Software Straight-line 3-10 years

Restructuring and Other Charg_2

Restructuring and Other Charges (Tables)	9 Months Ended
Restructuring and Other Charges (Tables)	Sep. 30, 2024
Restructuring and Related Activities [Abstract]
Schedule of Restructuring Charges and Asset Disposals	The following table shows other charges included in Restructuring and other charges in the condensed consolidated statements of operations: Three Months Ended September 30, Nine Months Ended September 30, (in Millions) 2024 2023 2024 2023 Restructuring charges: Severance-related and exit costs $ 0.6 $ — $ 14.7 $ 2.4 Other charges: Costs related to the Allkem Livent Merger 12.2 13.6 99.0 32.3 Bessemer City plant fire - gain, net of insurance recoveries — (5.0) — — Other (3.1) 0.1 (2.3) 0.3 Total Restructuring and other charges $ 9.7 $ 8.7 $ 111.4 $ 35.0

Other gains_(losses) (Tables)

Other gains/(losses) (Tables)	9 Months Ended
Other gains/(losses) (Tables)	Sep. 30, 2024
Other Income and Expenses [Abstract]
Schedule of Other gains	The following table shows amounts included in Other gains/(losses) in the condensed consolidated statements of operations: Three Months Ended September 30, Nine Months Ended September 30, (in Millions) 2024 2023 2024 2023 Blue Chip Swap gains: (1) Non-recurring - SDV and MdA Holdings LLC (2) $ 8.7 $ 10.0 $ 45.2 $ 21.4 Recurring - SDJ and MdA 5.7 — 19.7 — Total Blue Chip Swap gains 14.4 10.0 64.9 21.4 Foreign currency remeasurement gains/(losses): Remeasurement gains on U.S. dollar denominated cash held by foreign currency functional subsidiary — — 14.3 — All other foreign currency remeasurement gains/(losses) (3) 30.9 (11.2) 123.7 (16.1) Total Foreign currency remeasurement gains/(losses) 30.9 (11.2) 138.0 (16.1) Loss on trading securities (0.5) — (0.9) — Total Other gains/(losses) $ 44.8 $ (1.2) $ 202.0 $ 5.3 ___________________________ 1. See Note 2 for details. 2. Represents the non-recurring gain from the sale in Argentina pesos of Argentina Sovereign U.S. dollar-denominated bonds due to the divergence of Argentina's Blue Chip Swap market exchange rate from the official rate. 3.

Debt (Tables)

Debt (Tables)	9 Months Ended
Debt (Tables)	Sep. 30, 2024
Debt Disclosure [Abstract]
Schedule of Long-Term Debt	Debt consists of the following: Interest Rate Percentage Maturity September 30, 2024 December 31, 2023 (in Millions) SOFR borrowings Base rate borrowings Revolving Credit Facility (1) 6.70% 8.75% 2027 $ 99.0 $ — 4.125% Convertible Senior Notes due 2025 4.125% 2025 245.8 245.8 Transaction costs - 2025 Notes (1.2) (2.4) Nemaska - Prepayment agreement - tranche 1 (2) 8.9% 75.0 75.0 Discount - Prepayment agreement (16.2) (19.8) Nemaska - Prepayment agreement - tranche 2 (2) 9.4% 150.0 — Discount - Prepayment agreement (47.5) — Nemaska - Other 0.5 3.4 Debt assumed in Allkem Livent Merger (3) Project Loan Facility - Stage 2 of Olaroz Plant 2.61% 2029 135.0 — Affiliate Loans with TTC 15.29% 2030 81.5 — Affiliate Loan with TLP 10.34% 2026 2.5 — Total debt assumed in Allkem Livent Merger 219.0 — Subtotal long-term debt (including current maturities) 724.4 302.0 Less current maturities (288.4) (2.4) Total long-term debt $ 436.0 $ 299.6 ______________________________ 1. As of September 30, 2024 and December 31, 2023, there were $20.7 million and $15.5 million, respectively, in letters of credit outstanding under our Revolving Credit Facility and $380.3 million and $484.5 million available funds as of September 30, 2024 and December 31, 2023, respectively. Fund availability is subject to the Company meeting its debt covenants. 2. Represents advance payments in connection with customer supply agreement which do not have a contractual interest rate or bear any actual interest and are repayable in equal quarterly installments beginning in January 2027 and ending in October 2031. Represents U.S. GAAP imputed interest rate. 3. On September 10, 2024, SDJ paid the outstanding principal balance of $9.1 million to repay Stage 1 of the Olaroz Plan Project Loan Facility in its entirety. On May 30, 2024, SDV paid the outstanding principal balance of $47.0 million, a prepayment fee of $0.9 million and accrued interest and commitment fees of $1.3 million to repay the Sal de Vida Project Financing Facility in its entirety.

Share-based Compensation (Table

Share-based Compensation (Tables)	9 Months Ended
Share-based Compensation (Tables)	Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]
Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan	We recognized the following share compensation expense for Legacy Livent Awards and awards under the Arcadium Plan: Three Months Ended September 30, Nine Months Ended September 30, (in Millions) 2024 Share Option Expense, net of taxes of $0.1 and $0.3 $ 0.7 $ 1.9 Restricted Share Expense, net of taxes of $0.1 and $1.2 2.8 19.8 Performance-Based Restricted Share Expense, net of taxes of zero and zero — 0.4 Total Share Compensation Expense, net of taxes of $0.2 and $1.5 (1) $ 3.5 $ 22.1 ____________________ (1) Gross share compensation charges of $3.4 million and $0.5 million were recorded to Selling, general and administrative expenses and Restructuring and other charges, respectively, in our condensed consolidated statements of operations for the three months ended September 30, 2024. Gross share compensation charges of $9.1 million and $14.5 million were recorded to Selling, general and administrative expenses and Restructuring and other charges, respectively, in our condensed consolidated statements of operations for the nine months ended September 30, 2024.
Schedule of Black Scholes Valuation Assumptions for Stock Option Grants	Black Scholes valuation assumptions for Arcadium Plan share options granted in 2024: Nine months ended September 30, 2024 Grant date 3/6/2024 5/14/2024 6/28/2024 7/30/2024 9/1/2024 Expected dividend yield —% —% —% —% —% Expected volatility 31.18% 31.97% 33.00% 33.22% 35.06% Expected life (in years) 6.0 6.0 6.0 6.0 6.0 Risk-free interest rate 4.08% 4.41% 4.28% 4.00% 3.72%
Schedule of Stock Option Activity	The following summary shows share option activity for the Allkem Livent Merger and the Arcadium Plan for the nine months ended September 30, 2024: Number of Options Granted But Not Exercised Weighted-Average Remaining Contractual Life Weighted-Average Exercise Price Per Share Aggregate Intrinsic Value (in Millions) Outstanding December 31, 2023 5,060,687 5.6 $ 6.73 $ 6.5 Granted 4,058,953 $ 4.82 Exercised (53,056) $ 4.05 $ — Forfeited (106,548) $ 5.67 Outstanding at September 30, 2024 8,960,036 6.9 $ 5.90 $ 0.1 Exercisable at September 30, 2024 4,118,374 4.3 $ 6.24 $ —
Schedule of Restricted Award Activity	The following table shows RSU activity for the Allkem Livent Merger and the Arcadium Plan for the nine months ended September 30, 2024 : Restricted Share Units Number of Weighted-Average Grant Date Fair Value Aggregate Intrinsic Value (in Millions) Nonvested December 31, 2023 2,287,088 $ 7.83 $ 17.1 Granted (1) 5,084,720 $ 4.90 Vested (2) (2,171,932) $ 7.01 Forfeited (164,009) $ 5.62 Nonvested September 30, 2024 5,035,867 $ 5.30 $ 14.4 ___________________ 1. The Company granted 1,080,825 Allkem Replacement Awards on January 12, 2024 pursuant to the Allkem Transaction Agreement. 2. Immediately prior to the Acquisition Date, 768,440 non-employee Director RSUs vested and were paid out in cash of $5.3 million pursuant to the Allkem Transaction Agreement. Performance-Based Restricted Share Units Number of Weighted-Average Grant Date Fair Value Aggregate Intrinsic Value (in Millions) Nonvested as of December 31, 2023 96,885 $ 9.42 $ 0.7 Vested (96,885) $ 9.42 Nonvested as of September 30, 2024 — $ — $ —

Equity (Tables)

Equity (Tables)	9 Months Ended
Equity (Tables)	Sep. 30, 2024
Equity [Abstract]
Schedule of Common Stock Issued and Outstanding	The following is a summary of Arcadium's ordinary shares issued and outstanding: Issued Treasury Outstanding Balance as of December 31, 2023 (1) 433,059,946 (263,669) 432,796,277 Issued to Allkem shareholders - Allkem Livent Merger 641,337,840 — 641,337,840 PRSU and RSU awards accelerated - Allkem Livent Merger 648,969 — 648,969 Arcadium RSU awards 371,750 — 371,750 Arcadium share option awards 8,497 — 8,497 Net sales of treasury shares - Arcadium NQSP — 1,154 1,154 Balance as of September 30, 2024 1,075,427,002 (262,515) 1,075,164,487 _____________________ 1. Balances outstanding as of December 31, 2023, representing predecessor Livent, have been adjusted to reflect the 2.406 Exchange Ratio.
Schedule of Accumulated Other Comprehensive Income (Loss)	Summarized below is the roll forward of accumulated other comprehensive loss, net of tax. (in Millions) Foreign currency adjustments Derivative Instruments Total Accumulated other comprehensive loss, net of tax as of December 31, 2023 $ (49.8) $ — $ (49.8) Other comprehensive (losses)/income before reclassifications (17.1) 0.2 (16.9) Amounts reclassified from accumulated other comprehensive loss — 0.1 0.1 Accumulated other comprehensive loss, net of tax as of September 30, 2024 $ (66.9) $ 0.3 $ (66.6) (in Millions) Foreign currency adjustments Derivative Instruments Total Accumulated other comprehensive loss, net of tax as of December 31, 2022 $ (51.0) $ — $ (51.0) Other comprehensive income before reclassifications (1.3) — (1.3) Amounts reclassified from accumulated other comprehensive loss — 0.2 0.2 Accumulated other comprehensive loss, net of tax as of September 30, 2023 $ (52.3) $ 0.2 $ (52.1)

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
Earnings Per Share (Tables)	Sep. 30, 2024
Earnings Per Share [Abstract]
Schedule of Calculation of Basic and Diluted Earnings Per Share	Earnings applicable to ordinary shares and ordinary shares used in the calculation of basic and diluted earnings per share are as follows: (in Millions, Except Share and Per Share Data) Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 (1) 2024 2023 (1) Numerator: Net income attributable to Arcadium Lithium plc $ 16.1 $ 87.4 $ 117.4 $ 292.4 Denominator: Weighted average ordinary shares outstanding - basic 1,075.1 432.4 1,067.8 432.3 Dilutive share equivalents from share-based plans 0.8 3.5 0.9 3.5 Dilutive share equivalents from 2025 Notes 67.7 67.7 67.7 67.7 Weighted average ordinary shares outstanding - diluted 1,143.6 503.6 1,136.4 503.5 Basic earnings per ordinary share $ 0.01 $ 0.20 $ 0.11 $ 0.68 Diluted earnings per ordinary share $ 0.01 $ 0.17 $ 0.10 $ 0.58 _____________________ 1.

Financial Instruments, Risk M_2

Financial Instruments, Risk Management and Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2024
Fair Value Disclosures [Abstract]
Schedule Of Financial Instrument Valuation Methods	Our other financial instruments include the following: Financial Instrument Valuation Method Foreign exchange forward contracts Estimated amounts that would be received or paid to terminate the contracts at the reporting date based on current market prices for applicable currencies.
Schedule of Fair Value of Derivative Instruments	The following table provides the gross fair value and net balance sheet presentation of our derivative instruments. The Company had no open derivative cash flow hedge contracts as of December 31, 2023. September 30, 2024 Gross Amount of Derivatives (in Millions) Designated as Cash Flow Hedges Derivative assets Foreign exchange contracts $ 0.4 Total derivative assets (1) 0.4 Net derivative assets $ 0.4 __________________ 1. Net balance is included in Prepaid and other current assets in the condensed consolidated balance sheets.
Schedule of Derivatives in Cash Flow Hedging Relationships	The following tables summarize the gains or losses related to our cash flow hedges and derivatives not designated as cash flow hedging instruments. Derivatives in Cash Flow Hedging Relationships (in Millions) Total Foreign Exchange Contracts Accumulated other comprehensive income, net of tax as of December 31, 2023 $ — Unrealized hedging gains, net of tax 0.2 Total derivatives instruments impact on comprehensive income, net of tax 0.2 Accumulated other comprehensive income, net of tax as of March 31, 2024 $ 0.2 Unrealized hedging gains, net of tax 0.1 Total derivatives instruments impact on comprehensive income, net of tax 0.1 Accumulated other comprehensive income, net of tax at June 30, 2024 $ 0.3 Unrealized hedging losses, net of tax (0.1) Reclassification of deferred hedging losses, net of tax 0.1 Total derivatives instruments impact on comprehensive income, net of tax — Accumulated other comprehensive income, net of tax at September 30, 2024 $ 0.3 (in Millions) Total Foreign Exchange Contracts Accumulated other comprehensive income, net of tax as of December 31, 2022 $ — Unrealized hedging gains, net of tax 0.2 Total derivatives instruments impact on comprehensive income, net of tax 0.2 Accumulated other comprehensive income, net of tax as of March 31, 2023 $ 0.2 Unrealized hedging gains, net of tax 0.4 Total derivatives instruments impact on comprehensive income, net of tax 0.4 Accumulated other comprehensive income, net of tax at June 30, 2023 $ 0.6 Unrealized hedging losses, net of tax (0.6) Reclassification of deferred hedging gains, net of tax 0.2 Total derivatives instruments impact on comprehensive income, net of tax (0.4) Accumulated other comprehensive income, net of tax at September 30, 2023 $ 0.2
Schedule of Derivatives Not Designated as Cash Flow Hedging Instruments	Location of Gain or (Loss) Amount of Pre-tax Gain or (Loss) Recognized in Income on Derivatives (1) Three Months Ended September 30, Nine Months Ended September 30, (in Millions) 2024 2023 2024 2023 Foreign Exchange contracts Other gain/(loss) $ 2.2 $ (0.1) $ 15.3 $ 1.8 Total $ 2.2 $ (0.1) $ 15.3 $ 1.8 ____________________ 1.
Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis	The following tables present our fair-value hierarchy for those assets and liabilities measured at fair-value on a recurring basis in our condensed consolidated balance sheets. (in Millions) September 30, 2024 Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Assets Investments in deferred compensation plan (1) $ 6.9 $ 6.9 $ — $ — JEMSE Receivable 5.0 — — 5.0 Equity securities (2) 0.7 0.7 — — Derivatives – Foreign exchange 0.4 — 0.4 — Total Assets $ 13.0 $ 7.6 $ 0.4 $ 5.0 Liabilities Deferred compensation plan obligation (3) $ 7.6 $ 7.6 $ — $ — Total Liabilities $ 7.6 $ 7.6 $ — $ — (in Millions) December 31, 2023 Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Assets Investments in deferred compensation plan (1) $ 4.1 $ 4.1 $ — — Total Assets $ 4.1 $ 4.1 $ — $ — Liabilities Deferred compensation plan obligation (3) $ 6.7 $ 6.7 $ — $ — Total Liabilities (4) $ 6.7 $ 6.7 $ — $ — ____________________ 1. Balance is included in Investments in the condensed consolidated balance sheets. Arcadium NQSP investments in Arcadium ordinary shares are recorded as Treasury shares in the condensed consolidated balance sheets and carried at historical cost. Mark-to-market gains of $0.1 million and $1.2 million were recorded for the three and nine months ended September 30, 2024, respectively. Mark-to-market gains of $1.0 million and $0.2 million were recorded for the three and nine months ended September 30, 2023, related to the Arcadium ordinary shares. The mark-to-market gains and losses were recorded in Selling, general and administrative expenses in the condensed consolidated statements of operations, with a corresponding offset to the deferred compensation plan obligation in the condensed consolidated balance sheets. 2. Mark-to-market gains and losses are recorded to Other gain/loss in the condensed consolidated statement of operations. 3. Balance is included in Other long-term liabilities in the condensed consolidated balance sheets. 4.

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
Commitments and Contingencies (Tables)	Sep. 30, 2024
Commitments and Contingencies Disclosure [Abstract]
Schedule of Lease Cost	Quantitative disclosures about our leases are summarized in the table below. Three Months Ended September 30, Nine Months Ended September 30, (in Millions, except for weighted-average amounts) 2024 2023 2024 2023 Lease Cost Operating lease cost $ 4.4 $ 0.4 $ 12.9 $ 1.0 Short-term lease cost 0.1 0.1 0.3 0.3 Total lease cost (1) $ 4.5 $ 0.5 $ 13.2 $ 1.3 Other information Cash paid for amounts included in the measurement of lease liabilities: Cash paid for operating leases $ 4.2 $ 0.4 $ 12.4 $ 1.1 __________________________ 1. Lease expense is classified as Selling, general and administrative expenses in our condensed consolidated statements of operations.
Schedule of Maturity Analysis of Operating Lease Liabilities	The table below presents a maturity analysis of our operating lease liabilities for each of the next five years and a total of the amounts for the remaining years. (in Millions) Undiscounted cash flows Remainder of 2024 $ 3.1 2025 10.3 2026 9.5 2027 8.8 2028 8.5 Thereafter 35.6 Total future minimum lease payments 75.8 Less: Imputed interest (19.3) Total $ 56.5

Supplemental Information (Table

Supplemental Information (Tables)	9 Months Ended
Supplemental Information (Tables)	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Prepaid and Other Assets	The following tables present details of prepaid and other current assets, other assets, accrued and other current liabilities, and other long-term liabilities as presented on the condensed consolidated balance sheets: (in Millions) September 30, 2024 December 31, 2023 Prepaid and other current assets Tax related items $ 100.8 $ 29.5 Prepaid expenses 51.0 16.9 Argentina government receivable (1) 42.2 7.9 Other receivables 48.4 28.2 Bank Acceptance Drafts (2) 1.7 — Derivative assets (Note 19) 0.4 — Other current assets 3.4 3.9 Total $ 247.9 $ 86.4 (in Millions) September 30, 2024 December 31, 2023 Other assets Argentina government receivable (1), (3) $ 119.6 $ 71.3 Advance to contract manufacturers (4) 27.4 27.6 Long-term semi-finished goods inventory 142.4 1.0 Tax related items 4.3 4.0 Capitalized software, net 1.8 1.1 Investment in transit - Nemaska Lithium (5) 43.9 — Other assets 50.0 22.7 Total $ 389.4 $ 127.7 _________________ 1. We have various subsidiaries that conduct business in Argentina. As of September 30, 2024 and December 31, 2023, $41.5 million and $38.8 million, respectively, of outstanding receivables due from the Argentina government, which primarily represent export tax and export rebate receivables, was denominated in U.S. dollars. A recent judicial decision relating to the U.S. dollar-denominated export tax receivable portion of $34.8 million permits the Argentina government to reimburse us in Argentine pesos at the historical foreign exchange rate applicable at each past payment date, adjusted by a bank deposit interest rate. While Arcadium filed an appeal on November 6, 2023 and believes it has valid defenses on the technical merits, the ultimate resolution of this matter could result in a possible loss of up to $34.3 million. We continually review the recoverability of all outstanding receivables by analyzing historical experience, current collection trends and regional business and political factors among other factors. 2. Bank Acceptance Drafts are a common Chinese finance note used to settle trade transactions. The Company accepts these notes from Chinese customers based on criteria intended to ensure collectability and limit working capital usage. 3. In June 2023, the Company decided to pay $21.7 million for the export duties and interest claimed by the Customs Authorities of Buenos Aires, Ezeiza and Salta related to exports made between the years 2018 – 2022 registered in those locations. This payment stops the accrual of any further interest. It was a deposit made under protest and was not an admission of any of the claims made by the Customs Authorities or a waiver of any of the Company's defenses, including recovery of the deposit plus interest. The cases remain in discussion. See Note 20 for more information. 4. We record deferred charges for certain contract manufacturing agreements which we amortize over the term of the underlying contract. 5. Represents the Company's cash contributed to Nemaska Lithium in the third quarter of 2024 which, due to one-quarter lag reporting, are not yet recorded in our consolidation of Nemaska. The balance is recorded to Other assets - noncurrent because the cash is expected to be used by Nemaska primarily for capital expenditures. IQ contemporaneously made an equal contribution in the third quarter of 2024 which, due to one-quarter lag reporting, is not recorded in our consolidation of Nemaska. See Note 9 for details.
Schedule of Accrued and Other Liabilities	(in Millions) September 30, 2024 December 31, 2023 Accrued and other current liabilities Accrued payroll $ 55.5 $ 31.2 Restructuring reserves 2.0 1.7 Retirement liability - 401k 3.6 3.2 Environmental reserves, current 2.8 0.5 Accrued investment in unconsolidated affiliates — 27.0 Other accrued and other current liabilities (1) 111.6 73.2 Total $ 175.5 $ 136.8 (in Millions) September 30, 2024 December 31, 2023 Other long-term liabilities Deferred compensation plan obligation $ 7.6 $ 6.7 Contingencies related to uncertain tax positions (2) 9.1 6.2 Self-insurance reserves 1.1 1.1 Asset retirement obligations 12.5 3.7 Other long-term liabilities 61.7 3.6 Total $ 92.0 $ 21.3 ____________________ 1. Amounts p rimarily include accrued capital expenditures related to our expansion projects. 2. As of September 30, 2024, we have recorded a liability for uncertain tax positions of $8.7 million and a $0.4 million indemnification liability where the offsetting uncertain tax position is with FMC, per the tax matters agreement.

Description of the Business (De

Description of the Business (Details) - USD ($) $ / shares in Units, $ in Millions	9 Months Ended
	Sep. 30, 2024	Oct. 09, 2024	Jan. 04, 2024	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Ordinary shares par value (in dollars per share)	$ 1		$ 1	$ 1	$ 1	$ 1
Rio Tinto
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Termination fees	$ 200
Rio Tinto \| Subsequent Event
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Ordinary shares par value (in dollars per share)		$ 1
Exchange right without interest (in dollars per share)		$ 5.85

Significant Accounting Polici_4

Significant Accounting Policies and Related Financial Information - Schedule of Impact of Reclassifications (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2024	Mar. 31, 2024	Sep. 30, 2023		Sep. 30, 2024	Sep. 30, 2023
Significant Accounting Policies [Line Items]
Cost of sales	$ 146.9	$ 154.8	$ 83.6	[1]	$ 475.8	$ 258.4	[1]
Restructuring and other charges		79.8	8.7			35
Other (gains)/losses	$ (44.8)	(77.3)	1.2	[1]	$ (202)	(5.3)	[1]
Prior Presentation
Significant Accounting Policies [Line Items]
Cost of sales		116.8	94.9			274.8
Restructuring and other charges		83.6	8.6			34.7
Other (gains)/losses		(43.1)	(10)			(21.4)
Loss/(gain) Reclassified
Significant Accounting Policies [Line Items]
Cost of sales		(38)	11.3			16.4
Restructuring and other charges		3.8	(0.1)			(0.3)
Other (gains)/losses		$ (34.2)	$ 11.2			$ 16.1

[1] For the three and nine months ended September 30, 2023, basic and diluted earnings per ordinary share and weighted average ordinary shares outstanding - basic and diluted amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Represents the results of predecessor Livent’s operations for three and nine months ended September 30, 2023 which do not include the operations of Allkem.

Significant Accounting Polici_5

Significant Accounting Policies and Related Financial Information - Narrative (Details) $ in Millions		3 Months Ended		9 Months Ended
	Aug. 02, 2024 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) segment	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)
Significant Accounting Policies [Line Items]
Number of reportable segments \| segment				1
Asset retirement obligation		$ 12.5		$ 12.5		$ 3.7
Realized foreign currency transaction gain		$ 14.4	$ 10	$ 64.9	$ 21.4
Li-Metal Corp
Significant Accounting Policies [Line Items]
Asset acquisition, consideration transferred	$ 11
Minimum
Significant Accounting Policies [Line Items]
Payment term (in days)				20 days
Maximum
Significant Accounting Policies [Line Items]
Payment term (in days)				180 days

Allkem Livent Merger - Narrativ

Allkem Livent Merger - Narrative (Details) $ / shares in Units, $ in Millions		3 Months Ended		9 Months Ended
	Jan. 04, 2024 USD ($) $ / shares shares	Sep. 30, 2024 USD ($) $ / shares	Sep. 30, 2023 USD ($) $ / shares	Sep. 30, 2024 USD ($) $ / shares	Sep. 30, 2023 USD ($) $ / shares		Dec. 31, 2023 $ / shares	Dec. 31, 2022 $ / shares
Business Acquisition [Line Items]
Ordinary shares par value (in dollars per share) \| $ / shares	$ 1	$ 1	$ 1	$ 1	$ 1		$ 1	$ 1
Conversion ratio	2.406
Decrease to deferred income tax liabilities				$ 27.7	$ 11.6	[1]
Costs related to the Allkem Livent Merger		$ 12.2	$ 13.6	99	$ 32.3
Livent Corporation
Business Acquisition [Line Items]
Ordinary shares par value (in dollars per share) \| $ / shares	$ 0.001
Allkem Livent Merger
Business Acquisition [Line Items]
Increase to property, plant and equipment				0.6
Decrease to deferred income tax assets				16.7
Increase to accounts payable trade and other				1.8
Decrease in income taxes				0.3
Decrease to environmental liabilities				9.1
Decrease to deferred income tax liabilities				27.7
Increase to other long term liabilities				3.7
Decrease in goodwill				$ 15.3
Trade receivables	$ 64.2
Property, plant and equipment	4,326.1
Allkem Livent Merger \| Mineral rights
Business Acquisition [Line Items]
Property, plant and equipment	2,745
Allkem Livent Merger \| Non Mining Properties and Mineral Rights
Business Acquisition [Line Items]
Property, plant and equipment	$ 1,581.1
Allkem Livent Merger \| Former Livent Stockholders
Business Acquisition [Line Items]
Number of shares issued in transaction (in shares) \| shares	433,156,855
Allkem Livent Merger \| Former Allkem Shareholders
Business Acquisition [Line Items]
Number of shares issued in transaction (in shares) \| shares	641,337,840
Allkem Livent Merger \| CHESS Depositary Instrument
Business Acquisition [Line Items]
Equity interest issued or issuable, share exchange ratio	1
Allkem Livent Merger \| CHESS Depositary Instrument \| Former Allkem Shareholders
Business Acquisition [Line Items]
Number of shares issued in transaction (in shares) \| shares	542,612,224
Allkem Livent Merger \| Ordinary Shares, $1.00 Per Share Par Value
Business Acquisition [Line Items]
Equity interest issued or issuable, share exchange ratio	1
Allkem Livent Merger \| Ordinary Shares, $1.00 Per Share Par Value \| Former Allkem Shareholders
Business Acquisition [Line Items]
Number of shares issued in transaction (in shares) \| shares	98,725,616
Allkem Livent Merger \| Performance Shares \| Former Livent Stockholders
Business Acquisition [Line Items]
Number of shares issued in transaction (in shares) \| shares	96,909

[1] Represents the results of predecessor Livent’s operations for nine months ended September 30, 2023, which do not include the operations of Allkem.

Allkem Livent Merger - Consider

Allkem Livent Merger - Consideration Transferred (Details) - Allkem Livent Merger $ in Millions	Jan. 04, 2024 USD ($)
Business Acquisition [Line Items]
Fair value of Arcadium ordinary shares issued to Allkem shareholders	$ 4,385.6
Fair value of converted Allkem performance rights attributable to pre-combination service	4.8
Total consideration	$ 4,390.4

Allkem Livent Merger - Purchase

Allkem Livent Merger - Purchase Price Allocation (Details) - USD ($) $ in Millions	Jan. 04, 2024	Sep. 30, 2024	Dec. 31, 2023
Liabilities assumed:
Goodwill		$ 1,293.2	$ 120.7	[1]
Allkem Livent Merger
Business Acquisition [Line Items]
Total consideration	$ 4,390.4
Assets acquired:
Cash and cash equivalents	681.4
Trade receivables	64.2
Inventories	121.3
Prepaid and other current assets	87.2
Property, plant and equipment	4,326.1
Right of use assets - operating leases, net	53.4
Deferred income tax assets	9.6
Other assets	192.7
Total assets acquired	5,535.9
Liabilities assumed:
Accounts payable, trade and other	223.7
Accrued and other current liabilities	35.1
Income taxes	78.5
Long-term debt including current portion	301.7
Operating lease liabilities - long-term	53.4
Environmental liabilities	9.8
Deferred income tax liabilities	1,289
Other long-term liabilities	53.2
Total liabilities assumed	2,044.4
Fair value of net assets acquired	3,491.5
Add: Fair value of noncontrolling interests acquired	275
Fair value of net assets acquired less noncontrolling interests acquired	3,216.5
Allkem
Liabilities assumed:
Goodwill	$ 1,173.9	$ 1,173.9	$ 0

[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

Allkem Livent Merger - Earnings

Allkem Livent Merger - Earnings Subsequent to the Closing Date of Transaction (Details) - Allkem Livent Merger - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2024
Business Acquisition [Line Items]
Revenue	$ 56.6	$ 242.9
(Loss)/income from operations before income taxes	$ (44.6)	$ 107.6

Allkem Livent Merger - Pro Form

Allkem Livent Merger - Pro Forma Information (Details) - Allkem Livent Merger - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2023
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Revenue	$ 538.5	$ 1,677.7
Net income	$ 299	$ 812.4

Goodwill (Details)

Goodwill (Details) $ in Millions	9 Months Ended
Goodwill (Details) $ in Millions	Sep. 30, 2024 USD ($)
Goodwill [Roll Forward]
Beginning balance	$ 120.7	[1]
Acquisitions - Allkem Livent Merger	1,189.2
Measurement period adjustments	(16.7)
Ending balance	1,293.2
Allkem
Goodwill [Roll Forward]
Beginning balance	0
Acquisitions - Allkem Livent Merger	1,189.2
Measurement period adjustments	(15.3)
Ending balance	1,173.9
Nemaska Lithium
Goodwill [Roll Forward]
Beginning balance	120.7
Acquisitions - Allkem Livent Merger	0
Measurement period adjustments	(1.4)
Ending balance	$ 119.3

[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

Revenue Recognition - Disaggreg

Revenue Recognition - Disaggregation of Revenue by Major Geographical Region (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023		Sep. 30, 2024	Sep. 30, 2023
Disaggregation of Revenue [Line Items]
Consolidated Revenue	$ 203.1	$ 211.4	[1]	$ 718.8	$ 700.7	[1]
Asia Pacific
Disaggregation of Revenue [Line Items]
Consolidated Revenue	172.4	163.8		604.3	502.4
North America
Disaggregation of Revenue [Line Items]
Consolidated Revenue	22.1	31.9		65.6	124.5
Europe, Middle East & Africa
Disaggregation of Revenue [Line Items]
Consolidated Revenue	8.6	15.6		47.6	72
Latin America
Disaggregation of Revenue [Line Items]
Consolidated Revenue	0	0.1		1.3	1.8
China
Disaggregation of Revenue [Line Items]
Consolidated Revenue	111.4	95.6		392.4	274.9
Japan
Disaggregation of Revenue [Line Items]
Consolidated Revenue	33.9	42.1		111.7	118.2
United States
Disaggregation of Revenue [Line Items]
Consolidated Revenue	21.7	30			120
South Korea
Disaggregation of Revenue [Line Items]
Consolidated Revenue	$ 24.8	$ 20.6		$ 89.8	$ 86.9

[1] For the three and nine months ended September 30, 2023, basic and diluted earnings per ordinary share and weighted average ordinary shares outstanding - basic and diluted amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Represents the results of predecessor Livent’s operations for three and nine months ended September 30, 2023 which do not include the operations of Allkem.

Revenue Recognition - Narrative

Revenue Recognition - Narrative (Details) - Revenue from Contract with Customer Benchmark - Customer Concentration Risk	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Customer One
Disaggregation of Revenue [Line Items]
Concentration risk percentage	25%	28%	23%	25%
Customer Two
Disaggregation of Revenue [Line Items]
Concentration risk percentage		25%	20%	22%
Ten Largest Customers
Disaggregation of Revenue [Line Items]
Concentration risk percentage	77%	78%	73%	70%

Revenue Recognition - Disaggr_2

Revenue Recognition - Disaggregation of Revenue By Major Product Category (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023		Sep. 30, 2024	Sep. 30, 2023
Disaggregation of Revenue [Line Items]
Consolidated Revenue	$ 203.1	$ 211.4	[1]	$ 718.8	$ 700.7	[1]
Lithium Hydroxide
Disaggregation of Revenue [Line Items]
Consolidated Revenue	85.6	142.8		309.3	449.2
Lithium Carbonate
Disaggregation of Revenue [Line Items]
Consolidated Revenue	56	9		208.5	23.6
Butyllithium and Other Lithium Specialties
Disaggregation of Revenue [Line Items]
Consolidated Revenue	39.4	59.6		130.2	227.9
Spodumene Concentrate
Disaggregation of Revenue [Line Items]
Consolidated Revenue	$ 22.1	$ 0		$ 70.8	$ 0

[1] For the three and nine months ended September 30, 2023, basic and diluted earnings per ordinary share and weighted average ordinary shares outstanding - basic and diluted amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Represents the results of predecessor Livent’s operations for three and nine months ended September 30, 2023 which do not include the operations of Allkem.

Revenue Recognition - Assets an

Revenue Recognition - Assets and Liabilities (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	[2]	Dec. 31, 2023	[1]
Revenue from Contract with Customer [Abstract]
Receivables from contracts with customers, net of allowances	$ 90.2			$ 106.7
Contract liability - short-term	55.1			4.4
Contract liability - long-term	251.2			$ 217.8
(Decrease)/increase receivables from contracts with customers, net of allowances	(16.5)
(Decrease)/increase contract liability - short-term	50.7	$ (5.8)
(Decrease)/increase contract liability - long-term	$ 33.4

[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem. Represents the results of predecessor Livent’s operations for nine months ended September 30, 2023, which do not include the operations of Allkem.

Revenue Recognition - Performan

Revenue Recognition - Performance Obligations (Details) - Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-10-01 $ in Billions	Sep. 30, 2024 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 1.6
Expected timing of satisfaction of performance obligations	5 years

Inventories, Net - Schedule of

Inventories, Net - Schedule of Inventory (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Inventory Disclosure [Abstract]
Finished goods	$ 139.9	$ 59.1
Semi-finished goods	143.6	108.8
Raw materials, supplies, and other	106.1	49.6
Inventory, net	$ 389.6	$ 217.5	[1]

[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

Investments - Equity Method Inv

Investments - Equity Method Investments (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Schedule of Equity Method Investments [Line Items]
Investments	$ 40	$ 34.8	[1]
ESM ILiAD, LLC
Schedule of Equity Method Investments [Line Items]
Investments	30.1	30.1
Arcadium NQSP
Schedule of Equity Method Investments [Line Items]
Investments	6.8	4.7
TLC (Naraha plant)
Schedule of Equity Method Investments [Line Items]
Investments	2.4	0
Other
Schedule of Equity Method Investments [Line Items]
Investments	$ 0.7	$ 0

[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

Investments - Narrative (Detail

Investments - Narrative (Details) - USD ($)	3 Months Ended			9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	[2]	Sep. 30, 2024	Sep. 30, 2023	[2],[3]	Dec. 31, 2023
Schedule of Equity Method Investments [Line Items]
Investment carrying amount	$ 40,000,000			$ 40,000,000			$ 34,800,000	[1]
Equity in net loss of unconsolidated affiliate	5,900,000	$ 6,700,000		5,900,000	$ 22,000,000
Loan receivable	$ 2,400,000			$ 2,400,000
Toyotsu Lithium Corporation
Schedule of Equity Method Investments [Line Items]
Ownership interest by parent percentage	75%			75%
Subsidiary, economic interest percentage, noncontrolling interest	51%			51%
Toyotsu Lithium Corporation \| Class A Voting Shares
Schedule of Equity Method Investments [Line Items]
Ownership interest by parent percentage	49%			49%
Toyotsu Lithium Corporation \| Class B Nonvoting Shares
Schedule of Equity Method Investments [Line Items]
Ownership interest by parent percentage	100%			100%
Toyota Tsusho Corporation
Schedule of Equity Method Investments [Line Items]
Ownership interest by parent percentage	49%			49%
Subsidiary, economic interest percentage, noncontrolling interest	25%			25%
Toyota Tsusho Corporation \| Class A Voting Shares
Schedule of Equity Method Investments [Line Items]
Ownership interest by parent percentage	51%			51%
ESM ILiAD, LLC
Schedule of Equity Method Investments [Line Items]
Investment carrying amount	$ 30,100,000			$ 30,100,000			$ 30,100,000
Toyotsu Lithium Corporation
Schedule of Equity Method Investments [Line Items]
Equity in net loss of unconsolidated affiliate	5,900,000			5,900,000
Loan receivable	$ 0			$ 0

[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem. For the three and nine months ended September 30, 2023, basic and diluted earnings per ordinary share and weighted average ordinary shares outstanding - basic and diluted amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Represents the results of predecessor Livent’s operations for three and nine months ended September 30, 2023 which do not include the operations of Allkem. Represents the results of predecessor Livent’s operations for nine months ended September 30, 2023, which do not include the operations of Allkem.

Partially-Owned Subsidiaries _2

Partially-Owned Subsidiaries and Noncontrolling Interests (Details) - USD ($) $ in Millions		3 Months Ended				9 Months Ended
		Dec. 31, 2024	Sep. 30, 2024	Sep. 30, 2023		Sep. 30, 2024	Sep. 30, 2023		Jun. 30, 2024	Dec. 31, 2023		Dec. 31, 2022
Schedule of Equity Method Investments [Line Items]
Loan receivable			$ 2.4			$ 2.4
Equity in net loss of unconsolidated affiliate			5.9	$ 6.7	[1]	5.9	$ 22	[1],[2]
Cash and cash equivalents			137.9			137.9				$ 237.6	[3]
Long-term debt			724.4			724.4				$ 302
Investment in-transit - Nemaska Lithium						(43.9)	0
Investments in unconsolidated affiliates (4)	[4]					40.7	85.4	[2]
Cash held in subsidiary entities			$ 42.6			$ 42.6
Investment interest-free loan repaid dividends percentage			33%			33%
Line of Credit
Schedule of Equity Method Investments [Line Items]
Restricted cash, noncurrent			$ 18.1			$ 18.1
Sales De Jujuy Pte Ltd
Schedule of Equity Method Investments [Line Items]
Ownership interest by parent percentage			72.68%			72.68%
Sales De Jujuy Pte Ltd \| Toyota Tsusho Corporation
Schedule of Equity Method Investments [Line Items]
Subsidiary, ownership percentage, noncontrolling owner			27.32%			27.32%
Sales De Jujuy S.A
Schedule of Equity Method Investments [Line Items]
Ownership interest by parent percentage			66.50%			66.50%
Sales De Jujuy S.A \| Jujuy Energia y Minera Sociedad del Estado
Schedule of Equity Method Investments [Line Items]
Subsidiary, ownership percentage, noncontrolling owner			8.50%			8.50%
Sales De Jujuy S.A \| Sales De Jujuy Pte Ltd
Schedule of Equity Method Investments [Line Items]
Ownership interest by parent percentage			91.50%			91.50%
Olaroz
Schedule of Equity Method Investments [Line Items]
Ownership interest by parent percentage			66.50%			66.50%
Olaroz \| Toyota Tsusho Corporation
Schedule of Equity Method Investments [Line Items]
Subsidiary, ownership percentage, noncontrolling owner			25%			25%
Olaroz \| Jujuy Energia y Minera Sociedad del Estado
Schedule of Equity Method Investments [Line Items]
Subsidiary, ownership percentage, noncontrolling owner			8.50%			8.50%
Nemaska Lithium Inc.
Schedule of Equity Method Investments [Line Items]
Equity interest percentage												50%
Loan receivable												$ 437.1
Equity in net loss of unconsolidated affiliate				$ 6.7			$ 22
Cash and cash equivalents									$ 42
Cumulative proceeds from supply agreement						$ 225
Long-term debt			$ 161.3			161.3
Contract liabilities from customers			63.7			63.7
Advances to contract manufacturers			$ 350			$ 350
Nemaska Lithium Inc. \| Subsequent Event
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated affiliates (4)		$ 22
Nemaska Lithium Inc. \| Investissement Québec \| Subsequent Event
Schedule of Equity Method Investments [Line Items]
Ownership interest by parent percentage		50%

[1] For the three and nine months ended September 30, 2023, basic and diluted earnings per ordinary share and weighted average ordinary shares outstanding - basic and diluted amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Represents the results of predecessor Livent’s operations for three and nine months ended September 30, 2023 which do not include the operations of Allkem. Represents the results of predecessor Livent’s operations for nine months ended September 30, 2023, which do not include the operations of Allkem. Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem. On October 18, 2023 we began consolidating Nemaska Lithium, see Note 9 for details.

Property, Plant and Equipment_3

Property, Plant and Equipment, Net (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Total cost	$ 7,594.7		$ 2,506.2
Accumulated depreciation	(345.5)		(269.1)
Property, plant and equipment, net	7,249.2		2,237.1	[1]
Depreciation	74.6	$ 21.5
Land and land improvements
Property, Plant and Equipment [Line Items]
Total cost	334.7		106.2
Buildings
Property, Plant and Equipment [Line Items]
Total cost	$ 985.3		134.9
Buildings \| Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	20 years
Buildings \| Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	40 years
Machinery and equipment
Property, Plant and Equipment [Line Items]
Total cost	$ 985.6		420.7
Mineral rights
Property, Plant and Equipment [Line Items]
Total cost	3,279.6		560
Construction in progress
Property, Plant and Equipment [Line Items]
Total cost	$ 2,009.5		$ 1,284.4
Land improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	20 years
Leased plant and equipment \| Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	1 year
Leased plant and equipment \| Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	10 years 6 months
Other machinery and equipment \| Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	3 years
Other machinery and equipment \| Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	18 years
Software \| Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	3 years
Software \| Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	10 years

[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

Property, Plant, and Equipment,

Property, Plant, and Equipment, Net - Narrative (Details) $ in Millions	3 Months Ended
	Sep. 30, 2024 USD ($)
Property, Plant and Equipment [Abstract]
Non-cash charge	$ 51.7

Restructuring and Other Charg_3

Restructuring and Other Charges - Restructuring Charges in Consolidated Income (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023		Sep. 30, 2024	Sep. 30, 2023
Restructuring charges:
Restructuring charges	$ 0.6	$ 0		$ 14.7	$ 2.4
Other charges:
Costs related to the Allkem Livent Merger	12.2	13.6		99	32.3
Bessemer City plant fire - gain, net of insurance recoveries	0	(5)		0	0
Other	(3.1)	0.1		(2.3)	0.3
Total Restructuring and other charges	$ 9.7	$ 8.7	[1]	$ 111.4	$ 35	[1]

[1] For the three and nine months ended September 30, 2023, basic and diluted earnings per ordinary share and weighted average ordinary shares outstanding - basic and diluted amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Represents the results of predecessor Livent’s operations for three and nine months ended September 30, 2023 which do not include the operations of Allkem.

Other gains_(losses) (Details)

Other gains/(losses) (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
Other gains/(losses) (Details) - USD ($) $ in Millions	Sep. 30, 2024	Mar. 31, 2024	Sep. 30, 2023		Sep. 30, 2024	Sep. 30, 2023
Other Income and Expenses [Abstract]
Non-recurring - SDV SA and MdA Holdings LLC	$ 8.7		$ 10		$ 45.2	$ 21.4
Recurring - SDJ and MdA	5.7		0		19.7	0
Total costs and expenses	14.4		10		64.9	21.4
Foreign currency remeasurement gains/(losses):
Remeasurement gains on U.S. dollar denominated cash held by foreign currency functional subsidiary	0		0		14.3	0
All other foreign currency remeasurement gains/(losses)	30.9		(11.2)		123.7	(16.1)
Total Foreign currency remeasurement gains/(losses)	30.9		(11.2)		138	(16.1)
Loss on trading securities	(0.5)		0		(0.9)	0
Total Other gains/(losses)	$ 44.8	$ 77.3	$ (1.2)	[1]	$ 202	$ 5.3	[1]

[1] For the three and nine months ended September 30, 2023, basic and diluted earnings per ordinary share and weighted average ordinary shares outstanding - basic and diluted amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Represents the results of predecessor Livent’s operations for three and nine months ended September 30, 2023 which do not include the operations of Allkem.

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
Income Taxes (Details) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023		Sep. 30, 2024	Sep. 30, 2023
Income Tax Disclosure [Abstract]
Income tax (benefit)/expense	$ (33.4)	$ 9.3	[1]	$ 55.7	$ 47.8	[1]
Effective tax rate	383.90%	9.60%		28.60%	14.10%

[1] For the three and nine months ended September 30, 2023, basic and diluted earnings per ordinary share and weighted average ordinary shares outstanding - basic and diluted amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Represents the results of predecessor Livent’s operations for three and nine months ended September 30, 2023 which do not include the operations of Allkem.

Asset Retirement Obligations (D

Asset Retirement Obligations (Details) - Allkem Livent Merger $ in Millions	Sep. 30, 2024 USD ($)
Mt Cattlin Spodumene Mine
Business Acquisition [Line Items]
Asset retirement obligations acquired	$ 7.3
Olaroz
Business Acquisition [Line Items]
Asset retirement obligations acquired	1.5
Galaxy Lithium (SAL DE VIDA) S.A
Business Acquisition [Line Items]
Asset retirement obligations acquired	$ 1

Debt - Long-term Debt (Details)

Debt - Long-term Debt (Details) - USD ($) $ in Millions	May 30, 2024	Sep. 30, 2024	Sep. 10, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Transaction costs/discount		$ (1.2)		$ (2.4)
Subtotal long-term debt (including current maturities)		724.4		302
Less current maturities		(288.4)		(2.4)	[1]
Long-term debt		436		299.6	[1]
Total debt assumed in Allkem Livent Merger
Debt Instrument [Line Items]
Subtotal long-term debt (including current maturities)		$ 219		0
Nemaska Lithium \| Prepayment Agreement Tranche One
Debt Instrument [Line Items]
Convertible debt, interest rate		8.90%
Transaction costs/discount		$ (16.2)		(19.8)
Nemaska - Prepayment agreement/Other		$ 75		75
Nemaska Lithium \| Prepayment Agreement Tranche Two
Debt Instrument [Line Items]
Convertible debt, interest rate		9.40%
Transaction costs/discount		$ (47.5)		0
Nemaska - Prepayment agreement/Other		150		0
Nemaska Lithium \| Other
Debt Instrument [Line Items]
Nemaska - Prepayment agreement/Other		$ 0.5		3.4
Line of Credit \| Project Loan Facility - Stage 2 of Olaroz Plant
Debt Instrument [Line Items]
Convertible debt, interest rate		2.6119%
Long-term debt, gross		$ 135		0
Line of Credit \| Affiliate Loans with TTC
Debt Instrument [Line Items]
Convertible debt, interest rate		15.29%
Long-term debt, gross		$ 81.5		0
Line of Credit \| Affiliate Loan with TLP
Debt Instrument [Line Items]
Convertible debt, interest rate		10.34%
Long-term debt, gross		$ 2.5		0
Line of Credit \| Project Financing Facility - Sal de Vida
Debt Instrument [Line Items]
Long-term debt, gross	$ 47
Prepayment fee	0.9
Deferred financing costs	$ 1.3
Line of Credit \| Project Loan Facility - Stage 1 of Olaroz Plant
Debt Instrument [Line Items]
Long-term debt, gross			$ 9.1
Convertible Debt
Debt Instrument [Line Items]
Convertible debt, interest rate		4.125%
Long-term debt, gross		$ 245.8		245.8
Revolving Credit Facility
Debt Instrument [Line Items]
Letters of credit outstanding, amount		20.7		15.5
Line of credit, remaining borrowing capacity		380.3		484.5
Revolving Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Long-term debt, gross		$ 99		$ 0
SOFR borrowings \| Revolving Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Credit facility, interest rate		6.70%
Base rate borrowings \| Revolving Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Credit facility, interest rate		8.75%

[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

Debt - Narrative (Details)

Debt - Narrative (Details) $ / shares in Units, $ in Millions			3 Months Ended			9 Months Ended			12 Months Ended
	May 30, 2024 USD ($)	Jan. 04, 2024 USD ($) $ / shares	Sep. 30, 2024 USD ($) $ / shares	Sep. 30, 2023 USD ($)	[1]	Sep. 30, 2024 USD ($) loan day $ / shares	Sep. 30, 2023 USD ($)	[1],[2]	Dec. 31, 2020 USD ($) day $ / shares	Dec. 31, 2023 USD ($)
Debt Instrument [Line Items]
Loss on debt extinguishment			$ 0	$ 0		$ 1.1	$ 0
Cash and cash equivalents			$ 137.9			$ 137.9				$ 237.6	[3]
Convertible Debt
Debt Instrument [Line Items]
Debt interest rate			4.125%			4.125%
Long-term debt, gross			$ 245.8			$ 245.8				245.8
Convertible Debt \| Conversion Circumstance One
Debt Instrument [Line Items]
Conversion price per share (in dollars per share) \| $ / shares			$ 4.72			$ 4.72
Percentage of conversion price						130%
Trading days \| day						20
Consecutive trading days \| day						30
Line of Credit
Debt Instrument [Line Items]
Restricted cash, noncurrent			$ 18.1			$ 18.1
Line of Credit \| Revolving Credit Facility
Debt Instrument [Line Items]
Long-term debt, gross			99			99				0
2025 Notes
Debt Instrument [Line Items]
Debt discount, excluding amortization			$ 2.5			$ 7.5
2025 Notes \| Convertible Debt
Debt Instrument [Line Items]
Debt interest rate			4.125%			4.125%			4.125%
Aggregate principal amount of debt									$ 245.8
Conversion price per share (in dollars per share) \| $ / shares		$ 3.63							$ 8.73
Percentage of conversion price									130%
Trading days \| day									20
Consecutive trading days \| day									30
Redemption price, percentage of principal amount									100%
Business day period \| day									5
Consecutive trading day period \| day									5
Trading price as percentage of closing price of common stock									98%
Amortization of discount and transaction costs			$ 0.4			$ 1.1
Conversion ratio (in shares)						0.275459331			0.1144885
Convertible Senior Notes, Over-Allotment Option \| Convertible Debt
Debt Instrument [Line Items]
Capital contribution from noncontrolling interest - Nemaska Lithium									$ 238.2
Payments of debt issuance costs									$ 7.6
Credit Agreement \| Line of Credit \| Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 500
Maximum increase in revolving credit commitments		$ 700
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration]		SOFR borrowings
Basis spread on variable rate		0.10%
Floor rate		0%
Commitment fee percentage		0.25%
Deferred financing costs						$ 0.8
Loss on debt extinguishment			0			0.2
Deferred financing costs			$ 2.3			$ 2.3
Net leverage ratio						3.5
Minimum interest coverage ratio						3.5
Credit Agreement \| Line of Credit \| Letter of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 50
Project Financing Facility - Sal de Vida \| Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 180
Deferred financing costs	1.3
Debt instruments, ownership percentage			1			1
Long-term debt, gross	47
Prepayment fee	$ 0.9
Project Loan Facility - Stage 2 of Olaroz Plant \| Line of Credit
Debt Instrument [Line Items]
Debt interest rate			2.6119%			2.6119%
Long-term debt, gross			$ 135			$ 135				0
Cash and cash equivalents			$ 101.3			$ 101.3
Fee for permitted reductions			0.025			0.025
Affiliate Loans with TTC \| Line of Credit
Debt Instrument [Line Items]
Debt interest rate			15.29%			15.29%
Aggregate principal amount of debt			$ 93			$ 93
Long-term debt, gross			$ 81.5			$ 81.5				$ 0
Number of loans \| loan						11

[1] For the three and nine months ended September 30, 2023, basic and diluted earnings per ordinary share and weighted average ordinary shares outstanding - basic and diluted amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Represents the results of predecessor Livent’s operations for three and nine months ended September 30, 2023 which do not include the operations of Allkem. Represents the results of predecessor Livent’s operations for nine months ended September 30, 2023, which do not include the operations of Allkem. Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

Share-based Compensation - Narr

Share-based Compensation - Narrative (Details) $ / shares in Units, $ in Millions			9 Months Ended
	Jan. 04, 2024 shares	Dec. 22, 2023	Sep. 30, 2024 USD ($) publicly_traded_peer $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Right to receive per share amount (in dollars per share) \| $ / shares			$ 5.85
Number of publicly traded peers \| publicly_traded_peer			10
Weighted average grant date fair value (in dollars per share) \| $ / shares			$ 1.89
Legacy Livent Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares authorized (in shares)			6,579,305
Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based payment award, expiration period (in years)			10 years
Unrecognized compensation cost related to unvested stock options \| $			$ 7.2
Requisite service period (in years)			2 years 4 months 24 days
RSU awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Requisite service period (in years)			2 years 2 months 12 days
Unrecognized compensation cost \| $			$ 18.6
Accelerated vesting, number (in shares)			927,510
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Accelerated vesting, number (in shares)	96,885
Performance Shares \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		100%
Arcadium Lithium Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares authorized (in shares)			64,548,000
Share-based payment award, expiration period (in years)			10 years

Share-based Compensation - Stoc

Share-based Compensation - Stock Compensation (Details) - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2024
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense, tax	$ 200,000	$ 1,500,000
Stock compensation expense	3,500,000	22,100,000
Selling, General and Administrative Expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Gross stock compensation charges	3,400,000	9,100,000
Restructuring Charges
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Gross stock compensation charges	500,000	14,500,000
Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense, tax	100,000	300,000
Stock compensation expense	700,000	1,900,000
RSU awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense, tax	100,000	1,200,000
Stock compensation expense	2,800,000	19,800,000
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense, tax	0	0
Stock compensation expense	$ 0	$ 400,000

Share-based Compensation - Blac

Share-based Compensation - Black Scholes Assumptions (Details) - Stock Option	Sep. 01, 2024	Jul. 30, 2024	Jun. 28, 2024	May 14, 2024	Mar. 06, 2024
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield	0%	0%	0%	0%	0%
Expected volatility	35.06%	33.22%	33%	31.97%	31.18%
Expected life (in years)	6 years	6 years	6 years	6 years	6 years
Risk-free interest rate	3.72%	4%	4.28%	4.41%	4.08%

Share-based Compensation - St_2

Share-based Compensation - Stock Option Activity (Details) $ / shares in Units, $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2024 USD ($) $ / shares shares	Dec. 31, 2023 USD ($) $ / shares shares
Number of Options Granted But Not Exercised
Beginning balance (in shares) \| shares	5,060,687
Granted (in shares) \| shares	4,058,953
Exercised (in shares) \| shares	(53,056)
Forfeited (in shares) \| shares	(106,548)
Ending balance (in shares) \| shares	8,960,036	5,060,687
Exercisable (in shares) \| shares	4,118,374,000
Weighted-Average Remaining Contractual Life (in Years)
Outstanding	6 years 10 months 24 days	5 years 7 months 6 days
Exercisable	4 years 3 months 18 days
Weighted-Average Exercise Price Per Share
Outstanding (in dollars per share) \| $ / shares	$ 6.73
Granted (in dollars per share) \| $ / shares	4.82
Exercised (in dollars per share) \| $ / shares	4.05
Forfeited (in dollars per share) \| $ / shares	5.67
Outstanding (in dollars per share) \| $ / shares	5.90	$ 6.73
Exercisable (in dollars per share) \| $ / shares	$ 6.24
Aggregate Intrinsic Value (in Millions)
Outstanding \| $	$ 0.1	$ 6.5
Exercised \| $	0
Exercisable \| $	$ 0

Share-based Compensation - RSU

Share-based Compensation - RSU and PRSU Activity (Details) - USD ($) $ / shares in Units, $ in Millions			9 Months Ended
	Jan. 12, 2024	Jan. 03, 2024	Sep. 30, 2024	Dec. 31, 2023
RSU awards
Number of awards
Nonvested, beginning balance (in shares)			2,287,088
Granted (in shares)	1,080,825		5,084,720
Vested (in shares)		(768,440)	(2,171,932)
Forfeited (in shares)			(164,009)
Nonvested, ending balance (in shares)			5,035,867
Weighted-Average Grant Date Fair Value
Nonvested, beginning balance (in dollars per share)			$ 7.83
Granted (in dollars per share)			4.90
Vested (in dollars per share)			7.01
Forfeited (in dollars per share)			5.62
Nonvested, ending balance (in dollars per share)			$ 5.30
Aggregate Intrinsic Value (in Millions)
Aggregate intrinsic value			$ 14.4	$ 17.1
Intrinsic value of awards vested		$ 5.3
Performance Shares
Number of awards
Nonvested, beginning balance (in shares)			96,885
Vested (in shares)			(96,885)
Nonvested, ending balance (in shares)			0
Weighted-Average Grant Date Fair Value
Nonvested, beginning balance (in dollars per share)			$ 9.42
Vested (in dollars per share)			9.42
Nonvested, ending balance (in dollars per share)			$ 0
Aggregate Intrinsic Value (in Millions)
Aggregate intrinsic value			$ 0	$ 0.7

Equity - Additional Information

Equity - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
Equity - Additional Information (Details) - USD ($)	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Jan. 04, 2024	Dec. 31, 2023	Dec. 31, 2022
Equity [Abstract]
Common stock, shares authorized (in shares)	5,000,000,000		5,000,000,000		5,000,000,000	5,000,000,000
Ordinary shares par value (in dollars per share)	$ 1	$ 1	$ 1	$ 1	$ 1	$ 1	$ 1
Preferred stock, shares authorized (in shares)	125,000,000		125,000,000		125,000,000
Preferred stock, par value (in dollars per share)	$ 1		$ 1		$ 1
Dividends paid	$ 0	$ 0	$ 0	$ 0

Equity - Summary of Common Stoc

Equity - Summary of Common Stock Activity (Details)	9 Months Ended
Equity - Summary of Common Stock Activity (Details)	Sep. 30, 2024 shares	Jan. 04, 2024	Dec. 31, 2023	Sep. 30, 2023
Issued
Beginning balance (in share)	433,059,946
Arcadium share option awards (in shares)	4,058,953
Ending balance (in share)	1,075,427,002
Treasury
Beginning balance (in shares)	(263,669)
Ending balance (in shares)	(262,515)
Outstanding
Beginning balance, outstanding (in shares)	432,796,277
Ending balance, outstanding (in shares)	1,075,164,487
Exchange ratio				2.406
Allkem Livent Merger
Outstanding
Exchange ratio		2.406
Ordinary Shares, $1.00 Per Share Par Value \| Allkem Livent Merger
Outstanding
Exchange ratio			2.406
Performance Share and Restricted Stock Units (RSUs), Accelerated Awards
Issued
PRSU and RSU awards accelerated - Allkem Livent Merger (in shares)	648,969
Arcadium RSU awards
Issued
PRSU and RSU awards accelerated - Allkem Livent Merger (in shares)	371,750
Ordinary Shares, $1.00 Per Share Par Value
Issued
Issued to Allkem shareholders - Allkem Livent Merger (in shares)	641,337,840
Livent Plan \| Performance Share and Restricted Stock Units (RSUs
Outstanding
Share issued during period (in shares)	648,969
Livent Plan \| Ordinary Shares, $1.00 Per Share Par Value
Outstanding
Share issued during period (in shares)	641,337,840
Arcadium
Treasury
Net sales of treasury (in shares)	1,154
Outstanding
Net sales of treasury shares - Arcadium NQSP (in shares)	1,154
Arcadium \| Arcadium RSU awards
Outstanding
Share issued during period (in shares)	371,750
Arcadium \| Arcadium share option awards
Issued
Arcadium share option awards (in shares)	8,497
Outstanding
Share issued during period (in shares)	8,497

Equity - Schedule of Accumulate

Equity - Schedule of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Millions		3 Months Ended						9 Months Ended
		Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	[1]			$ 1,784.2				$ 1,784.2
Other comprehensive (losses)/income before reclassifications		$ (0.1)
Ending balance		6,296.1						6,296.1
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance				(49.8)			$ (51)	(49.8)	$ (51)
Other comprehensive (losses)/income before reclassifications								(16.9)	(1.3)
Reclassification of deferred hedging gains, net of tax								0.1	0.2
Ending balance		(66.6)			$ (52.1)			(66.6)	(52.1)
Foreign currency adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance				(49.8)			(51)	(49.8)	(51)
Other comprehensive (losses)/income before reclassifications								(17.1)	(1.3)
Reclassification of deferred hedging gains, net of tax								0	0
Ending balance		(66.9)			(52.3)			(66.9)	(52.3)
Derivative Instruments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		0.3	$ 0.2	0	0.6	$ 0.2	0	0	0
Other comprehensive (losses)/income before reclassifications			0.1	0.2	(0.6)	0.4	0.2	0.2	0
Reclassification of deferred hedging gains, net of tax		0.1			0.2			0.1	0.2
Ending balance		$ 0.3	$ 0.3	$ 0.2	$ 0.2	$ 0.6	$ 0.2	$ 0.3	$ 0.2

[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

Earnings Per Share - EPS Calcul

Earnings Per Share - EPS Calculation (Details) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2024 USD ($) $ / shares shares	Sep. 30, 2023 USD ($) $ / shares shares		Sep. 30, 2024 USD ($) $ / shares shares	Sep. 30, 2023 USD ($) $ / shares shares
Numerator:
Net income attributable to Arcadium Lithium plc \| $	$ 16.1	$ 87.4	[1]	$ 117.4	$ 292.4	[1]
Denominator:
Weighted average ordinary shares outstanding - basic (in shares)	1,075.1	432.4	[1]	1,067.8	432.3	[1]
Dilutive share equivalents from share-based plans (in shares)	0.8	3.5		0.9	3.5
Dilutive share equivalents from 2025 Notes (in shares)	67.7	67.7		67.7	67.7
Weighted average ordinary shares outstanding - diluted (in shares)	1,143.6	503.6	[1]	1,136.4	503.5	[1]
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share [Abstract]
Basic earnings per ordinary share (in dollars per share) \| $ / shares	$ 0.01	$ 0.20	[1]	$ 0.11	$ 0.68	[1]
Earnings Per Share, Diluted [Abstract]
Diluted earnings per ordinary share (in dollars per share) \| $ / shares	$ 0.01	$ 0.17	[1]	$ 0.10	$ 0.58	[1]
Exchange ratio		2.406			2.406

[1] For the three and nine months ended September 30, 2023, basic and diluted earnings per ordinary share and weighted average ordinary shares outstanding - basic and diluted amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Represents the results of predecessor Livent’s operations for three and nine months ended September 30, 2023 which do not include the operations of Allkem.

Earnings Per Share - Narrative

Earnings Per Share - Narrative (Details) - $ / shares	3 Months Ended		9 Months Ended
Earnings Per Share - Narrative (Details) - $ / shares	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive securities, exercise price (in dollars per share)			$ 4.82
Stock Option
Antidilutive Securities Excluded from Computation of Earnings Per Share
Total antidilutive weighted average share equivalents (in shares)	9,163,458	435,544	8,211,667	353,128
Antidilutive securities, exercise price (in dollars per share)	$ 5.90	$ 9.70	$ 6.19	$ 9.70

Financial Instruments, Risk M_3

Financial Instruments, Risk Management and Fair Value Measurements - Narrative (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Derivative [Line Items]
Long-term debt	$ 724.4	$ 302
Open foreign currency forward contracts designated as cash flow hedges, U.S. dollar equivalent	10.7
Forward Contracts
Derivative [Line Items]
AOCI, net	0.3
Foreign Exchange Contract \| Not Designated as Hedging Instrument
Derivative [Line Items]
Open foreign currency forward contracts designated as cash flow hedges, U.S. dollar equivalent	115.1
Estimate of Fair Value Measurement
Derivative [Line Items]
Long-term debt value	$ 772.9

Financial Instruments, Risk M_4

Financial Instruments, Risk Management and Fair Value Measurements - Schedule of Fair Value of Derivative Instruments (Details) $ in Millions	Sep. 30, 2024 USD ($)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total derivative assets	$ 0.4
Net derivative assets	0.4
Foreign Exchange contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total derivative assets	$ 0.4

Financial Instruments, Risk M_5

Financial Instruments, Risk Management and Fair Value Measurements - Derivatives in Cash Flow Hedging Relationships (Details) - USD ($) $ in Millions		3 Months Ended							9 Months Ended
		Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023		Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	[1]			$ 1,784.2					$ 1,784.2
Unrealized hedging gains (losses), net of tax		$ (0.1)
Other comprehensive income/(loss), net of tax		13.4			$ (2.2)	[2]			(16.8)	$ (1.1)	[2]
Ending balance		6,296.1							6,296.1
Derivative Instruments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		0.3	$ 0.2	0	0.6		$ 0.2	$ 0	0	0
Unrealized hedging gains (losses), net of tax			0.1	0.2	(0.6)		0.4	0.2	0.2	0
Reclassification of deferred hedging gains, net of tax		0.1			0.2				0.1	0.2
Other comprehensive income/(loss), net of tax		0	0.1	0.2	(0.4)		0.4	0.2
Ending balance		$ 0.3	$ 0.3	$ 0.2	$ 0.2		$ 0.6	$ 0.2	$ 0.3	$ 0.2

[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem. Represents the results of predecessor Livent’s operations for three and nine months ended September 30, 2023, which do not include the operations of Allkem.

Financial Instruments, Risk M_6

Financial Instruments, Risk Management and Fair Value Measurements - Derivatives Not Designated As Cash Flow Hedging Instruments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Derivative [Line Items]
Amount of pre-tax gain or (loss) recognized in income on derivatives	$ 2.2	$ (0.1)	$ 15.3	$ 1.8
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Nonoperating Gains (Losses)	Other Nonoperating Gains (Losses)	Other Nonoperating Gains (Losses)	Other Nonoperating Gains (Losses)
Foreign Exchange contracts
Derivative [Line Items]
Amount of pre-tax gain or (loss) recognized in income on derivatives	$ 2.2	$ (0.1)	$ 15.3	$ 1.8

Financial Instruments, Risk M_7

Financial Instruments, Risk Management and Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Assets
Investments in deferred compensation plan	$ 6.9		$ 6.9		$ 4.1
JEMSE Receivable	5		5
Equity securities	0.7		0.7
Derivatives – Foreign exchange	0.4		0.4
Total Assets	13		13		4.1
Liabilities
Deferred compensation plan obligation	7.6		7.6		6.7
Total Liabilities	7.6		7.6		6.7
Selling, General and Administrative Expenses
Liabilities
Mark-to-market gains (loss) on deferred compensation plan	0.1	$ 1	1.2	$ 0.2
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets
Investments in deferred compensation plan	6.9		6.9		4.1
JEMSE Receivable	0		0
Equity securities	0.7		0.7
Derivatives – Foreign exchange	0		0
Total Assets	7.6		7.6		4.1
Liabilities
Deferred compensation plan obligation	7.6		7.6		6.7
Total Liabilities	7.6		7.6		6.7
Significant Other Observable Inputs (Level 2)
Assets
Investments in deferred compensation plan	0		0		0
JEMSE Receivable	0		0
Equity securities	0		0
Total Assets	0.4		0.4		0
Liabilities
Deferred compensation plan obligation	0		0		0
Total Liabilities	0		0		0
Significant Unobservable Inputs (Level 3)
Assets
Investments in deferred compensation plan	0		0		0
JEMSE Receivable	5		5
Equity securities	0		0
Derivatives – Foreign exchange	0		0
Total Assets	5		5		0
Liabilities
Deferred compensation plan obligation	0		0		0
Total Liabilities	$ 0		$ 0		$ 0

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) $ in Millions	Sep. 30, 2024 USD ($)	Sep. 06, 2024 lawsuit	Jan. 04, 2024 USD ($)	Oct. 31, 2023	Oct. 26, 2023	Feb. 28, 2023	Feb. 08, 2023
Lessor, Lease, Description [Line Items]
Export rate, percent of FOB value					1.50%	4%
Export LA Puna rate, percent of FOB value							0.025
Remaining export rate, percent of FOB value				0.015			0.015
Number of classaction lawsuits \| lawsuit		2
Operating lease, weighted average remaining lease term (in years)	8 years 4 months 24 days
Operating lease, weighted average discount rate (as a percent)	8.60%
Minera Del Altiplano
Lessor, Lease, Description [Line Items]
Export rebate receivable	$ 5.1
Sales De Jujuy S.A
Lessor, Lease, Description [Line Items]
Export rebate receivable	$ 1.5
Allkem Livent Merger
Lessor, Lease, Description [Line Items]
Right of use assets - operating leases, net			$ 53.4
Operating lease liabilities - long-term			$ 53.4
Minimum
Lessor, Lease, Description [Line Items]
Lessee, operating lease, remaining lease term	2 years
Maximum
Lessor, Lease, Description [Line Items]
Lessee, operating lease, remaining lease term	27 years

Commitments and Contingencies_2

Commitments and Contingencies - Lease Cost (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Lease Cost
Operating lease cost	$ 4.4	$ 0.4	$ 12.9	$ 1
Short-term lease cost	0.1	0.1	0.3	0.3
Total lease cost	4.5	0.5	13.2	1.3
Cash paid for amounts included in the measurement of lease liabilities:
Cash paid for operating leases	$ 4.2	$ 0.4	$ 12.4	$ 1.1

Commitments and Contingencies_3

Commitments and Contingencies - Maturity Analysis of Operating Lease Liabilities (Details) $ in Millions	Sep. 30, 2024 USD ($)
Undiscounted cash flows
Remainder of 2024	$ 3.1
2025	10.3
2026	9.5
2027	8.8
2028	8.5
Thereafter	35.6
Total future minimum lease payments	75.8
Less: Imputed interest	(19.3)
Total	$ 56.5

Supplemental Information - Prep

Supplemental Information - Prepaid and Other Current Assets (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Prepaid and other current assets
Tax related items	$ 100.8	$ 29.5
Prepaid expenses	51	16.9
Argentina government receivable	42.2	7.9
Other receivables	48.4	28.2
Bank Acceptance Drafts	1.7	0
Derivative assets (Note 19)	0.4	0
Other current assets	3.4	3.9
Total	$ 247.9	$ 86.4	[1]

[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

Supplemental Information - Othe

Supplemental Information - Other Assets (Details) - USD ($) $ in Millions	1 Months Ended	9 Months Ended
	Jun. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	[2]	Dec. 31, 2023		Nov. 06, 2023
Other assets
Argentina government receivable		$ 119.6			$ 71.3
Advance to contract manufacturers		27.4			27.6
Long-term semi-finished goods inventory		142.4			1
Tax related items		4.3			4
Capitalized software, net		1.8			1.1
Investment in transit - Nemaska Lithium		43.9			0
Other assets		50			22.7
Total		389.4			127.7	[1]
Condensed Balance Sheet Statements, Captions [Line Items]
Export tax receivable portion		34.8
Payment of deposit to customs authorities	$ 21.7	0	$ 21.7
Argentina Government
Condensed Balance Sheet Statements, Captions [Line Items]
Export tax and export rebate receivable		$ 41.5			$ 38.8
Settlement amount to be paid							$ 34.3

[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem. Represents the results of predecessor Livent’s operations for nine months ended September 30, 2023, which do not include the operations of Allkem.

Supplemental Information - Accr

Supplemental Information - Accrued and Other Current Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Accrued and other current liabilities
Accrued payroll	$ 55.5	$ 31.2
Restructuring reserves	2	1.7
Retirement liability - 401k	3.6	3.2
Environmental reserves, current	2.8	0.5
Accrued investment in unconsolidated affiliates	0	27
Other accrued and other current liabilities	111.6	73.2
Accrued and other liabilities	$ 175.5	$ 136.8	[1]

[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

Supplemental Information - Ot_2

Supplemental Information - Other Long-Term Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Other long-term liabilities
Deferred compensation plan obligation	$ 7.6	$ 6.7
Contingencies related to uncertain tax positions	9.1	6.2
Self-insurance reserves	1.1	1.1
Asset retirement obligations	12.5	3.7
Other long-term liabilities	61.7	3.6
Total	92	$ 21.3	[1]
TMA Agreement, Uncertain Tax Positions
Other long-term liabilities
Contingencies related to uncertain tax positions	8.7
TMA Agreement, Indemnification Liability
Other long-term liabilities
Contingencies related to uncertain tax positions	$ 0.4

[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.