Amphenol (APH) 424B5Prospectus supplement for primary offering

 Filed Pursuant to Rule 424(b)(5)​

 Registration No. 333-270605​

The date of this prospectus supplement is April 2, 2024.

The accompanying prospectus provides you with a general description of the senior debt securities, and this prospectus supplement contains specific information about the terms of this offering of the notes. This prospectus supplement, or the information incorporated by reference in this prospectus supplement or the accompanying prospectus, may add, update or change information contained in the accompanying prospectus. If information in this prospectus supplement, or the information incorporated by reference in this prospectus supplement, is inconsistent with the accompanying prospectus, this prospectus supplement, or the information incorporated by reference in this prospectus supplement, will apply and will modify or supersede that information in the accompanying prospectus.

Before making your investment decision, you should read and carefully consider this prospectus supplement and the accompanying prospectus, together with the additional information in the documents referred to in the sections entitled “Where You Can Find More Information” in the accompanying prospectus and “Incorporation of Certain Information by Reference” in this prospectus supplement.

Unless otherwise stated, or the context otherwise requires, references in this prospectus supplement to “we,” “us,” “our,” “Amphenol,” “APH” and “the Company” are to Amphenol Corporation and, as applicable, its consolidated subsidiaries, except for purposes of the description of the notes included in this prospectus supplement and the accompanying prospectus, where references to such terms refer only to Amphenol Corporation and do not include Amphenol Corporation’s subsidiaries. When we refer to the “notes” in this prospectus supplement, we mean the notes being offered by this prospectus supplement, unless we state otherwise.

This prospectus supplement, the accompanying prospectus and the documents incorporated by reference herein and therein, include forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 and the provisions of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. Such forward-looking statements are based on our management’s assumptions and beliefs about future events or circumstances using information currently available, and as a result, they are subject to risks and uncertainties. Forward- looking statements address events or developments that Amphenol Corporation expects or believes may or will occur in the future. These forward-looking statements, which address the Company’s expected business and financial performance and financial condition, among other matters, may contain words and terms such as: “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “forecast,” “guidance,” “intend,” “look ahead,” “may,” “ongoing,” “optimistic,” “plan,” “potential,” “predict,” “project,” “seek,” “should,” “target,” “will” or “would” and other words and terms of similar meaning.

on our business or that we are unable to predict or identify at the time of our Annual Report on Form 10-K for the fiscal year ended December 31, 2023. Our forward-looking statements may also be impacted by, among other things, future tax, regulatory and other legal changes that may arise in any of the jurisdictions in which we operate.

The Company undertakes no obligation to update or revise any forward-looking statements except as required by law.

our credit ratings with major credit rating agencies;

the prevailing interest rates being paid by other companies similar to us;

the market price of our common shares;

our financial condition, operating performance and future prospects;

the market for similar securities;

the overall condition of the financial markets; and

the interest of securities dealers in making a market for the notes.

proceeds distributed in connection with any insolvency, liquidation, reorganization, dissolution or other winding up of the Company.

Our New Revolving Credit Facility and the indenture that will govern the notes contain various covenants that limit our ability and the ability of our subsidiaries to, among other things:

incur certain liens;

enter into certain sale and leaseback transactions with respect to any of our Principal Property (as defined under “Description of Senior Debt Securities — Definitions” in the accompanying prospectus);

consolidate or merge with or into, or sell substantially all of our assets to, another person;

make accounting changes, except as required or permitted under generally accepted accounting principles;

make a material change to the nature of our business; and

engage in speculative transactions.

In addition, our New Revolving Credit Facility contains a financial maintenance covenant limiting the ratio of debt to earnings before interest, taxes, depreciation and amortization and limits on incurrence of certain liens. Although we were in compliance with this covenant as of December 31, 2023, the ability to meet the financial maintenance covenant can be affected by events beyond our control, and we cannot provide assurance that we will continue to meet this test. A breach of certain covenants under the New Revolving Credit Facility could also result in a default under our other indebtedness. Upon the occurrence of an event of default under any of our indebtedness, the lenders could elect to declare all amounts outstanding thereunder to be immediately due and payable and terminate all commitments to extend further credit. If the lenders accelerate the repayment of borrowings, we may not have sufficient assets to repay our New Revolving Credit Facility and other indebtedness, including these notes.

Event would cause a default under the indenture that will govern the notes, which could result in defaults under our other debt agreements and have material adverse consequences for us and the holders of the notes.

In addition, case law suggests that, in the event that incumbent directors are replaced as a result of a contested election, issuers may nevertheless avoid triggering a change of control under a clause similar to third bullet of the definition of “Change of Control” under the caption “Description of the Notes — Change of Control” in this prospectus supplement, if the outgoing directors were to approve the new directors for the purpose of avoiding the triggering of such change of control clause.

We have the right to redeem some or all of the notes prior to maturity, as described under “Description of the Notes — Optional Redemption” in this prospectus supplement. We may redeem the notes at times when prevailing interest rates may be relatively low. Accordingly, you may not be able to reinvest the redemption proceeds in a comparable security at an effective interest rate as high as the interest rate of the notes being redeemed.

The notes will be unsecured and effectively subordinated in right of payment to any future secured indebtedness to the extent of the assets securing such indebtedness. Although the indenture limits our ability to incur liens on our Principal Property (as defined under “Description of Senior Debt Securities — Definitions” in the accompanying prospectus), the notes will be effectively subordinated to any future debt secured by Principal Property to the extent permitted by the indenture or secured by any of our other assets. In the event of our liquidation or insolvency or other events of default on any such secured debt or upon acceleration of the notes in accordance with their terms, we will be permitted to make payment on the notes only after any such secured debt has been paid in full. After paying any such secured debt in full, we may not have sufficient assets remaining to pay any or all amounts due on the notes. In the event of our bankruptcy, liquidation or reorganization or upon acceleration of the notes, payment on the notes could be less, ratably, than on any such secured debt.

The notes will be structurally subordinated to any indebtedness of our subsidiaries. Our subsidiaries are separate and distinct legal entities, and none of our subsidiaries will guarantee the notes or otherwise have any obligations to make payments in respect of the notes. As a result, claims of holders of the notes will be effectively subordinated to the indebtedness and other liabilities of our subsidiaries. In the event of any bankruptcy, liquidation, dissolution or similar proceeding involving one of our subsidiaries, any of our rights or the rights of the holders of the notes to participate in the assets of that subsidiary will be effectively subordinated to the claims of creditors of that subsidiary, and following payment by that subsidiary of its liabilities, the subsidiary may not have sufficient assets remaining to make payments to us as a shareholder or otherwise. As of December 31, 2023, our subsidiaries (other than Amphenol Technologies Holding GmbH, the issuer of the 2026 Euro Notes and the 2028 Euro Notes, which are guaranteed by us) would have had approximately $32.2 million of indebtedness to which the notes would have been structurally subordinated.

In addition, certain of our subsidiaries are guarantors under our New Revolving Credit Facility. Accordingly, the notes will be structurally subordinated to such subsidiaries’ obligations to guarantee our indebtedness under our New Revolving Credit Facility.

The notes are exclusively our obligations. Our cash flow and our ability to service our indebtedness, including the notes, is partially dependent upon the earnings of our subsidiaries. In addition, we are particularly dependent on the distribution of earnings, loans or other payments by our subsidiaries to us. Our subsidiaries are separate and distinct legal entities. Our subsidiaries will have no obligation to pay any amounts due on the notes or to provide us with funds for our payment obligations, whether by dividends,

distributions, loans or other payments. In addition, any payment of dividends, distributions, loans or advances by our subsidiaries to us could be subject to statutory or contractual restrictions. Payments to us by our subsidiaries will also be contingent upon our subsidiaries’ earnings and business considerations. Our right to receive any assets of any subsidiary upon its liquidation or reorganization, and, therefore, our right to participate in those assets, will be effectively subordinated to the claims of that subsidiary’s creditors, including trade creditors. In addition, even if we were a creditor of any of our subsidiaries, our right as a creditor would be subordinate to any security interest in the assets of our subsidiaries and any indebtedness of our subsidiaries senior to the indebtedness held by us.

In any case where the date of payment of the principal of or premium, if any, or interest on the notes, including the date, if any, fixed for redemption or repurchase of the notes, shall not be a “business day” ​(as defined below), then payment of principal, premium or interest need not be made on that date at such place but may be made on the next succeeding business day, with the same force and effect as if made on the applicable payment date or the date fixed for redemption or repurchase, and no interest shall accrue for the period after that date. A “business day” shall mean a day that is not, in Hartford, Connecticut, a Saturday, Sunday, a legal holiday or a day on which banking institutions are authorized or obligated by law to close.

Prior to the Par Call Date (as defined below), we may redeem the notes of any series at our option, in whole or in part, at any time and from time to time, at a redemption price (expressed as a percentage of principal amount and rounded to three decimal places) equal to the greater of:

(1) (a) the sum of the present values of the remaining scheduled payments of principal and interest thereon discounted to the redemption date (assuming the notes matured on the Par Call Date) on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Rate plus 10 basis points in the case of the 2027 notes, 15 basis points in the case of the 2029 notes and 15 basis points in the case of the 2034 notes, in each case less (b) interest accrued to the date of redemption, and

On or after the applicable Par Call Date, we may redeem the notes of any series, at our option, in whole or in part, at any time and from time to time, at a redemption price equal to 100% of the principal amount of the notes being redeemed plus accrued and unpaid interest thereon to the redemption date.

yields — one yield corresponding to the Treasury constant maturity on H.15 immediately shorter than and one yield corresponding to the Treasury constant maturity on H.15 immediately longer than the Remaining Life — and shall interpolate to the Par Call Date on a straight-line basis (using the actual number of days) using such yields and rounding the result to three decimal places; or (3) if there is no such Treasury constant maturity on H.15 shorter than or longer than the Remaining Life, the yield for the single Treasury constant maturity on H.15 closest to the Remaining Life. For purposes of this paragraph, the applicable Treasury constant maturity or maturities on H.15 shall be deemed to have a maturity date equal to the relevant number of months or years, as applicable, of such Treasury constant maturity from the redemption date.

If on the third business day preceding the redemption date H.15 TCM is no longer published, we shall calculate the Treasury Rate based on the rate per annum equal to the semi-annual equivalent yield to maturity at 11:00 a.m., New York City time, on the second business day preceding such redemption date of the United States Treasury security maturing on, or with a maturity that is closest to, the Par Call Date, as applicable. If there is no United States Treasury security maturing on the Par Call Date but there are two or more United States Treasury securities with a maturity date equally distant from the Par Call Date, one with a maturity date preceding the Par Call Date and one with a maturity date following the Par Call Date, we shall select the United States Treasury security with a maturity date preceding the Par Call Date. If there are two or more United States Treasury securities maturing on the Par Call Date or two or more United States Treasury securities meeting the criteria of the preceding sentence, we shall select from among these two or more United States Treasury securities the United States Treasury security that is trading closest to par based upon the average of the bid and asked prices for such United States Treasury securities at 11:00 a.m., New York City time. In determining the Treasury Rate in accordance with the terms of this paragraph, the semi-annual yield to maturity of the applicable United States Treasury security shall be based upon the average of the bid and asked prices (expressed as a percentage of principal amount) at 11:00 a.m., New York City time, of such United States Treasury security, and rounded to three decimal places.

Our actions and determinations in determining the redemption price shall be conclusive and binding for all purposes, absent manifest error.

Notice of any redemption will be mailed or electronically delivered (or otherwise transmitted in accordance with the depositary’s procedures) at least 10 days but not more than 60 days before the redemption date to each holder of notes to be redeemed.

In the case of a partial redemption, selection of the notes for redemption will be made pro rata, by lot or by such other method as the Trustee in its sole discretion deems appropriate and fair. No notes of a principal amount of $2,000 or less will be redeemed in part. If any note is to be redeemed in part only, the notice of redemption that relates to the note will state the portion of the principal amount of the note to be redeemed. A new note in a principal amount equal to the unredeemed portion of the note will be issued in the name of the holder of the note upon surrender for cancellation of the original note. For so long as the notes are held by DTC (or another depositary), the redemption of the notes shall be done in accordance with the policies and procedures of the depositary.

Unless we default in payment of the redemption price, on and after the redemption date interest will cease to accrue on the notes or portions thereof called for redemption.

Except as described above and under the special mandatory redemption provision described below, the notes will not be redeemable by us prior to maturity and will not be entitled to the benefit of any sinking fund.

We may acquire notes by means other than a redemption, whether by tender offer, open market purchases, negotiated transactions or otherwise, in accordance with applicable securities laws, so long as such acquisition does not otherwise violate the terms of the indenture.

The trustee shall not be responsible for performing or verifying any calculations required in connection with a redemption.

The notes will be senior unsecured and unsubordinated indebtedness and will rank equally with all of our existing and future senior unsecured and unsubordinated indebtedness, including the 2025 Notes, the

2026 Notes, the 2029 Notes, the 2030 Notes, the 2031 Notes and the indebtedness evidenced by our guarantee of the 2026 Euro Notes and the 2028 Euro Notes issued by our subsidiary, Amphenol Technologies Holding GmbH, and any borrowings under our New Revolving Credit Facility. However, the notes are structurally subordinated to the indebtedness of our subsidiaries and effectively subordinated to any future secured indebtedness to the extent of the value of the assets securing such indebtedness.

As of December 31, 2023, on a pro forma as adjusted basis after giving effect to this offering and the application of the net proceeds from this offering as more fully described in “Use of Proceeds” in this prospectus supplement:

The notes will be structurally subordinated to any indebtedness of our subsidiaries. The 2026 Euro Notes and the 2028 Euro Notes, which are guaranteed by us, constitute our general senior unsecured obligations and rank equally in right of payment with our existing and future unsecured and unsubordinated indebtedness, including the notes offered hereby. Our subsidiaries are separate and distinct legal entities, and none of our subsidiaries will guarantee the notes or otherwise have any obligations to make payments in respect of the notes. As a result, claims of holders of the notes will be effectively subordinated to the indebtedness and other liabilities of our subsidiaries. In the event of any bankruptcy, liquidation, dissolution or similar proceeding involving one of our subsidiaries, any of our rights or the rights of the holders of the notes to participate in the assets of that subsidiary will be effectively subordinated to the claims of creditors of that subsidiary, and following payment by that subsidiary of its liabilities, the subsidiary may not have sufficient assets remaining to make payments to us as a shareholder or otherwise. In addition, certain of our subsidiaries are guarantors under our New Revolving Credit Facility. Accordingly, the notes will be structurally subordinated to such subsidiaries’ obligations to guarantee our indebtedness under our New Revolving Credit Facility.

We are obligated to pay reasonable compensation to the trustee and to indemnify the trustee against certain losses, liabilities and expenses incurred by the trustee in connection with its duties relating to the notes. The trustee’s claims for these payments will generally be senior to those of holders of the notes in respect of all funds collected or held by the trustee.

We intend to use the net proceeds from this offering, together with a combination of cash on hand and other debt financing, to pay the cash consideration for the CIT Acquisition and the payment of fees and expenses related to the CIT Acquisition and, to the extent that the net proceeds from this offering are not used for such purposes, for general corporate purposes, as described under the heading “Use of Proceeds.” The closing of this offering is expected to occur prior to the consummation of the CIT Acquisition. Each series of the notes will be subject to a “special mandatory redemption” in the event that (i) the CIT Acquisition is not consummated on or prior to the later of (x) January 30, 2025 (the “Outside Date”) or (y) the date that is five business days after any later date to which the parties to the Stock Purchase Agreement may agree to extend the Outside Date in the Stock Purchase Agreement (the “Special Mandatory Redemption End Date”), or (ii) we notify the trustee under the indenture that we will not pursue consummation of the CIT Acquisition. We refer to each of such events as a “special mandatory redemption event.” If a special mandatory redemption event occurs, we will be required to redeem the outstanding notes of each series at the “special mandatory redemption price” equal to 101% of the principal amount thereof plus accrued and unpaid interest from the date of initial issuance, or the most recent date to which interest has been paid or provided for, whichever is later, to, but not including, the special mandatory redemption date. The “special

mandatory redemption date” will be selected by us and will be a date no later than ten business day following the occurrence of the special mandatory redemption event. Unless we default in payment of the special mandatory redemption price, on and after such special mandatory redemption date, interest on the notes will cease to accrue.

The trustee will promptly as practicable mail, or cause the paying agent to promptly mail, to each holder of notes so tendered, the Change of Control Payment for such notes, and the trustee will promptly as practicable authenticate and mail (or cause to be transferred by book entry) to each holder a new note equal in principal amount to any unpurchased portion of the notes surrendered, if any, provided that each such new note will be in a principal amount of $2,000 and integral multiples of $1,000 in excess thereof.

If the Change of Control Payment Date is on or after an interest record date and on or before the related interest payment date, any accrued and unpaid interest, if any, will be paid to the person in whose name a note is registered at the close of business on such interest record date, and no additional interest will be payable to holders who tender pursuant to the Change of Control Offer.

Except as described above with respect to a Change of Control Repurchase Event, the indenture does not contain provisions that permit the holders to require us to repurchase or redeem the notes in the event of a takeover, recapitalization or similar transaction.

We will not be required to make the Change of Control Offer upon a Change of Control Repurchase Event if a third party makes an offer in the manner, at the times and otherwise in compliance with the requirements set forth in the indenture applicable to the Change of Control Offer made by us and repurchases all notes validly tendered and not withdrawn under such offer.

We will comply, to the extent applicable, with the requirements of Rule 14e-1 under the Exchange Act and any other securities laws or regulations thereunder to the extent those laws and regulations are applicable in connection with the repurchase of the notes as a result of a Change of Control Repurchase Event. To the extent that the provisions of any such securities laws or regulations conflict with the Change of Control Offer provisions of the notes, we will comply with those securities laws and regulations and will not be deemed to have breached our obligations under the Change of Control Offer provisions of the notes by virtue of any such conflict.

Our ability to repurchase notes pursuant to the Change of Control Offer may be limited by a number of factors. Certain events that may constitute a change of control under our other senior indebtedness and indebtedness of our subsidiaries and cause a default under the agreements related to such indebtedness may not constitute a Change of Control Repurchase Event under the indenture. Our New Revolving Credit Facility provides that the occurrence of certain change of control events would constitute a default thereunder. Future indebtedness of ours and our subsidiaries may also contain prohibitions of certain events that would constitute a Change of Control Repurchase Event or require such indebtedness to be repurchased upon a Change of Control Repurchase Event. Moreover, any exercise by the holders of our outstanding

senior notes of their right to require us to repurchase their notes could cause a default under such indebtedness, even if a Change of Control Repurchase Event itself does not, due to the financial effect of such repurchases on us. Finally, our ability to pay cash to the holders upon a repurchase may be limited by our then existing financial resources. We cannot assure you that sufficient funds will be available when necessary to make any required repurchases. See “Risk Factors — We may not be able to repurchase the notes upon a Change of Control Repurchase Event.”

Notwithstanding the foregoing, a transaction will not be considered to be a Change of Control if (a) we become a direct or indirect wholly owned subsidiary of a holding company and (b) immediately following that transaction, (1) the direct or indirect holders of the Voting Stock of the holding company are substantially the same as the holders of our Voting Stock immediately prior to that transaction or (2) no person or group is the beneficial owner, directly or indirectly, of more than a majority of the total voting power of the Voting Stock of the holding company.

As set forth in the indenture, we will be required, so long as any of the notes are outstanding, to file with the trustee (electronically or in hard copy), within 15 days after we file the same with the SEC, copies of the annual reports and of the information, documents and other reports (or copies of such portions of any of the foregoing as the SEC may from time to time by rules and regulations prescribe) that we may be required to file with the SEC pursuant to Section 13 or 15(d) of the Exchange Act; or, if we are not required to file information, documents or reports pursuant to either of such Sections, then we will file with the trustee and the SEC, in accordance with the rules and regulations prescribed from time to time by the SEC, such supplementary and periodic information, documents and reports that may be required pursuant to Section 13 of the Exchange Act in respect of a security listed and registered on a national securities exchange as may be prescribed from time to time in such rules and regulations. We will be deemed to have furnished

The following discussion is a summary of the material U.S. federal income tax consequences relevant to the purchase, ownership and disposition of the notes issued pursuant to this offering, but does not purport to be a complete analysis of all potential tax effects. The effects of other U.S. federal tax laws, such as estate and gift tax laws, and any applicable state, local or foreign tax laws are not discussed. This discussion is based on the U.S. Internal Revenue Code of 1986, as amended (the “Code”), Treasury Regulations promulgated thereunder, judicial decisions, and published rulings and administrative pronouncements of the U.S. Internal Revenue Service (the “IRS”), in each case in effect as of the date hereof. These authorities may change or be subject to differing interpretations. Any such change or differing interpretation may be applied retroactively in a manner that could adversely affect a holder of the notes. We have not sought and will not seek any rulings from the IRS regarding the matters discussed below. There can be no assurance the IRS or a court will not take a contrary position to that discussed below regarding the tax consequences of the purchase, ownership and disposition of the notes.

This discussion is limited to holders who hold the notes as “capital assets” within the meaning of Section 1221 of the Code (generally, property held for investment). In addition, this discussion is limited to persons purchasing the notes for cash at original issue and at their original “issue price” within the meaning of Section 1273 of the Code (i.e., the first price at which a substantial amount of the notes of the applicable series is sold to the public for cash). It is anticipated, and this discussion assumes, that the notes will be issued with no more than a de minimis amount of original issue discount for U.S. federal income tax purposes. In certain circumstances (see “Description of the Notes — Optional Redemption”, “Description of the Notes — Special Mandatory Redemption,” and “Description of the Notes — Change of Control”), we may be obligated to redeem the notes prior to their scheduled maturity and/or to pay amounts in excess of stated interest or principal on the notes. We intend to take the position that the possibility of such redemption or payments does not result in the notes being treated as contingent payment debt instruments or being issued with original issue discount under the applicable Treasury Regulations. Such position is not binding on the IRS. Prospective investors should consult their tax advisors regarding the tax consequences if the notes were treated as contingent payment debt instruments. The remainder of this discussion assumes that the notes are not treated as contingent payment debt instruments.

This discussion does not address all U.S. federal income tax consequences relevant to a holder’s particular circumstances, including the impact of the Medicare contribution tax on net investment income. In addition, it does not address consequences relevant to holders subject to special rules, including, without limitation:

U.S. expatriates and former citizens or long-term residents of the United States;

persons subject to any alternative minimum tax;

persons subject to special tax accounting rules as a result of any item of gross income with respect to the notes being taken into account in an applicable financial statement;

U.S. Holders (as defined below) whose functional currency is not the U.S. dollar;

persons holding the notes as part of a hedge, straddle or other risk reduction strategy or as part of a conversion transaction or other integrated investment;

banks, insurance companies, and other financial institutions;

real estate investment trusts or regulated investment companies;

brokers, dealers or traders in securities;

“controlled foreign corporations,” “passive foreign investment companies,” and corporations that accumulate earnings to avoid U.S. federal income tax;

S corporations, partnerships or other entities or arrangements treated as partnerships for U.S. federal income tax purposes (and investors therein);

tax-exempt organizations or governmental organizations; and

persons deemed to sell the notes under the constructive sale provisions of the Code.

For purposes of this discussion, a “U.S. Holder” is a beneficial owner of a note that, for U.S. federal income tax purposes, is or is treated as:

Interest on a note generally will be taxable to a U.S. Holder as ordinary income at the time such interest is received or accrued, in accordance with such U.S. Holder’s method of tax accounting for U.S. federal income tax purposes.

A U.S. Holder will recognize gain or loss on the sale, exchange, redemption, retirement or other taxable disposition of a note. The amount of such gain or loss will generally equal the difference between the amount received for the note in cash or other property valued at fair market value (less amounts attributable to any accrued but unpaid interest, which will be taxable as interest to the extent not previously included in income) and the U.S. Holder’s adjusted tax basis in the note. A U.S. Holder’s adjusted tax basis in a note generally will be equal to the amount the U.S. Holder paid for the note. Any gain or loss will be capital gain or loss, and will be long-term capital gain or loss if the U.S. Holder has held the note for more than one year at the time of sale or other taxable disposition. Otherwise, such gain or loss will be short-term capital gain or loss. Long-term capital gains recognized by certain non-corporate U.S. Holders, including individuals, generally will be taxable at a reduced rate. The deductibility of capital losses is subject to limitations.

A U.S. Holder may be subject to information reporting and backup withholding when such holder receives payments on a note or receives proceeds from the sale or other taxable disposition of a note (including a redemption or retirement of a note). Certain U.S. Holders are exempt from backup withholding, including corporations and certain tax-exempt organizations. A U.S. Holder will generally be subject to backup withholding if such holder is not otherwise exempt and the holder:

(or other applicable documentation), certifying that interest paid on a note is not subject to withholding tax because it is effectively connected with the conduct by the Non-U.S. Holder of a trade or business within the United States.

Any such effectively connected interest generally will be subject to U.S. federal income tax on a net income basis at the regular rates applicable to United States persons. A Non-U.S. Holder that is a corporation also may be subject to a branch profits tax at a rate of 30% (or such lower rate specified by an applicable income tax treaty) on such effectively connected interest, as adjusted for certain items.

The certifications described above must be provided to the applicable withholding agent prior to the payment of interest and may be required to be updated periodically. Non-U.S. Holders that do not timely provide the applicable withholding agent with the required certification, but that qualify for a reduced rate under an applicable income tax treaty, may obtain a refund of any excess amounts withheld by timely filing an appropriate claim for refund with the IRS. Non-U.S. Holders should consult their tax advisors regarding their entitlement to benefits under any applicable income tax treaty.

A Non-U.S. Holder will not be subject to U.S. federal income tax on any gain realized upon the sale, exchange, redemption, retirement or other taxable disposition of a note (such amount excludes any amount allocable to accrued and unpaid interest, which generally will be treated as interest and may be subject to the rules discussed above in “— Payments of Interest”) unless:

the gain is effectively connected with the Non-U.S. Holder’s conduct of a trade or business within the United States (and, if required by an applicable income tax treaty, the Non-U.S. Holder maintains a permanent establishment in the United States to which such gain is attributable); or

the Non-U.S. Holder is a nonresident alien individual present in the United States for 183 days or more during the taxable year of the disposition and certain other requirements are met.

Gain realized by a Non-U.S. Holder described in the first bullet point above generally will be subject to U.S. federal income tax on a net income basis at the regular rates applicable to United States persons. A Non-U.S. Holder that is a corporation also may be subject to a branch profits tax at a rate of 30% (or such lower rate specified by an applicable income tax treaty) on such effectively connected gain, as adjusted for certain items.

Gain realized by a Non-U.S. Holder described in the second bullet point above will be subject to U.S. federal income tax at a rate of 30% (or such lower rate specified by an applicable income tax treaty) and may be offset by U.S. source capital losses of the Non-U.S. Holder (even though the individual is not considered a resident of the United States), provided the Non-U.S. Holder has timely filed U.S. federal income tax returns with respect to such losses.

Any Plan fiduciary that proposes to cause a Plan to purchase or hold the notes should consult with its counsel regarding the potential applicability of the fiduciary responsibility and prohibited transaction provisions of Title I of ERISA, Section 4975 of the Code or applicable Similar Laws to such an investment, and to confirm that such purchase and holding will not constitute or result in a non-exempt prohibited transaction or any other violation of an applicable requirement of ERISA, Section 4975 of the Code or applicable Similar Law. In considering an investment in the notes with a portion of the assets of any Plan, a fiduciary should determine whether the investment is in accordance with the documents and instruments governing the Plan and the applicable provisions of ERISA, the Code or Similar Laws relating to a fiduciary’s duties to the Plan including, without limitation, the prudence, diversification, delegation of control and prohibited transaction provisions of ERISA, the Code and any other applicable Similar Laws.

Section 406 of ERISA and Section 4975 of the Code prohibit Covered Plans from engaging in specified transactions involving Covered Plan assets with persons or entities who are “parties in interest,” within the meaning of ERISA, or “disqualified persons,” within the meaning of Section 4975 of the Code, unless an exemption is available. Those sections further prohibit a fiduciary from engaging in transactions in which a conflict of interest is deemed present. A party in interest or disqualified person (including a fiduciary) who engaged in a non-exempt prohibited transaction may be subject to excise taxes and other penalties and liabilities under ERISA and/or the Code. In addition, the fiduciary of a Covered Plan that engaged in such a non-exempt prohibited transaction may be subject to penalties and liabilities under ERISA and/or the Code. The acquisition and/or holding of the notes by a Covered Plan with respect to which the issuer, any subsidiary guarantor, an underwriter or any of our or their respective affiliates may be considered a party in interest or a disqualified person may constitute or result in a direct or indirect prohibited transaction under Section 406 of ERISA and/or Section 4975 of the Code, unless the investment is acquired and is held in accordance with an applicable statutory, class or individual prohibited transaction exemption.

In this regard, the U.S. Department of Labor has issued prohibited transaction class exemptions, or “PTCEs,” that may provide exemptive relief for direct or indirect prohibited transactions resulting from the sale, purchase or holding of the notes. These class exemptions include, without limitation, PTCE 84-14 respecting transactions determined by independent qualified professional asset managers, PTCE 90-1 respecting insurance company pooled separate accounts, PTCE 91-38 respecting bank collective investment funds, PTCE 95-60 respecting life insurance company general accounts and PTCE 96-23 respecting transactions determined by in-house asset managers, although there can be no assurance that all of the conditions of any such exemptions will be satisfied. In addition to the foregoing, Section 408(b)(17) of ERISA and Section 4975(d)(20) of the Code provide exemptions for certain transactions between a Covered Plan and a person that is a party in interest and/or a disqualified person (other than a fiduciary or an affiliate that,

In connection with this offering of the notes, the underwriters may engage in overallotments, stabilizing transactions and syndicate covering transactions in accordance with Regulation M under the Exchange Act. Overallotment involves sales in excess of the offering size, which creates a short position for the underwriters. Stabilizing transactions involve bids to purchase the notes in the open market for the purpose of pegging, fixing or maintaining the price of the notes, as applicable. Syndicate covering transactions involve purchases of the notes in the open market after the distribution has been completed in order to cover short positions. Stabilizing transactions and syndicate covering transactions may cause the price of the notes to be higher than it would otherwise be in the absence of those transactions. If the underwriters engage in stabilizing or syndicate covering transactions, they may discontinue them at any time.

Certain of the underwriters and their affiliates have, from time to time, performed, and may in the future perform, various financial advisory, commercial banking and investment banking services for us and our affiliates for which they received, or will receive, customary fees and expenses. Standard Chartered Bank will not effect any offers or sales of any notes in the United States unless it is through one or more U.S. registered broker-dealers as permitted by the regulations of FINRA. In addition, U.S. Bancorp Investments, Inc., one of the underwriters, is an affiliate of the trustee.

In addition, in the ordinary course of their various business activities, the underwriters and their respective affiliates may make or hold a broad array of investments and actively trade debt and equity securities (or related derivative securities) and financial instruments (including bank loans) for their own account and for the accounts of their customers, and such investment and securities activities may involve securities and instruments of ours or our affiliates. Certain of the underwriters and their affiliates that have a lending relationship with us routinely hedge, and certain other of those underwriters or their affiliates may hedge, their credit exposure to us consistent with their customary risk management policies. Typically, such underwriters and their affiliates would hedge such exposure by entering into transactions which consist of either the purchase of credit default swaps or the creation of short positions in our securities, including potentially the notes offered hereby. Any such credit default swaps or short positions could adversely affect future trading prices of the notes offered hereby. The underwriters and their respective affiliates may also make investment recommendations or publish or express independent research views in respect of such securities or financial instruments and may at any time hold, or recommend to clients that they acquire, long or short positions in such securities and instruments.

This prospectus supplement and the accompanying prospectus have not been registered as a prospectus with the Monetary Authority of Singapore. Accordingly, this prospectus supplement, the accompanying prospectus and any other document or material in connection with the offer or sale, or invitation for subscription or purchase, of such notes may not be circulated or distributed, nor may the notes be offered or sold, or be made the subject of an invitation for subscription or purchase, whether directly or indirectly, to any person in Singapore other than:

Where the notes are subscribed or purchased under Section 275 of the SFA by a relevant person which is:

Singapore Securities and Futures Act Product Classification — Solely for the purposes of its obligations pursuant to sections 309B(1)(a) and 309B(1)(c) of the SFA, the Issuer has determined, and hereby notify all relevant persons (as defined in Section 309A of the SFA) that the notes are “prescribed capital markets products” ​(as defined in the Securities and Futures (Capital Markets Products) Regulations 2018) and Excluded Investment Products (as defined in MAS Notice SFA 04-N12: Notice on the Sale of Investment Products and MAS Notice FAA-N16: Notice on Recommendations on Investment Products).

Notes issued pursuant to this prospectus supplement must not be offered for sale (or transferred, assigned or otherwise alienated) to any person located in, or a resident of, Australia for at least 12 months after their issue, except in circumstances where the person is a person to whom a disclosure document or product disclosure statement is not required to be given under Chapter 6D or Chapter 7.9 of the Corporations Act.

We may offer and sell these senior debt securities, on a continuous or delayed basis, to or through one or more underwriters, dealers or agents, or directly to purchasers. If any underwriters, dealers or agents are involved in the sale of any of the senior debt securities, their names and any applicable purchase price, fee, commission or discount arrangement between or among them will be set forth, or will be calculable from the information set forth, in the applicable prospectus supplement. See the sections of this prospectus entitled “About this Prospectus” and “Plan of Distribution” for more information. No senior debt securities may be sold without delivery of this prospectus and the applicable prospectus supplement describing the method and terms of the offering of such senior debt securities.

This prospectus provides you with a general description of the senior debt securities we may offer. Each time we sell senior debt securities, we will provide a prospectus supplement that accompanies this prospectus that will provide specific information about the terms of that offering and the offered senior debt securities, including the specific amounts and prices of the senior debt securities offered. The accompanying prospectus supplement may include or incorporate by reference a detailed and current discussion of any risk factors and will discuss any special considerations applicable to those securities, including the plan of distribution. We may also authorize one or more free writing prospectuses to be provided to you that may contain material information relating to these offerings. The accompanying prospectus supplement or free writing prospectus may also add, update or change information contained in this prospectus. You should read both this prospectus and any prospectus supplement together with additional information described under “Where You Can Find More Information.” Any information in the accompanying prospectus supplement or free writing prospectus that is inconsistent with this prospectus will modify or supersede the information in this prospectus.

The registration statement we filed with the SEC includes exhibits that provide more detail of the matters discussed in this prospectus. Statements contained in this prospectus about the provisions or contents of any agreement or other document are not necessarily complete. If the SEC’s rules and regulations require that an agreement or document be filed as an exhibit to the registration statement, please see that agreement or document for a complete description of these matters.

Before making your investment decision, you should read and carefully consider this prospectus, the accompanying prospectus supplement (and any applicable free writing prospectuses), and the related exhibits filed with the SEC, together with the additional information in the documents referred to in the sections entitled “Where You Can Find More Information” and “Incorporation of Certain Information by Reference” below. Information incorporated by reference after the date of this prospectus is considered a part of this prospectus and may add, update or change information contained in this prospectus. Any information in such subsequent filings that is inconsistent with this prospectus will modify or supersede the information in this prospectus.

We have not authorized anyone to provide you with any information or to make any representations other than those contained in this prospectus, any applicable accompanying prospectus supplement or any free writing prospectuses prepared by or on behalf of us or to which we have referred you. We take no responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. We will not make an offer to sell these securities in any jurisdiction where the offer or sale is not permitted. You should assume that the information appearing in this prospectus and the applicable accompanying prospectus supplement to this prospectus is accurate only as of the date on its respective cover, that the information appearing in any applicable free writing prospectus is accurate only as of the date of that free writing prospectus, and that any information incorporated by reference is accurate only as of the date of the document incorporated by reference, unless we indicate otherwise. Our business, financial condition, results of operations and prospects may have changed since those dates. This prospectus incorporates by reference, and any accompanying prospectus supplement or free writing prospectus may contain and incorporate by reference, market data and industry statistics and forecasts that are based on independent industry publications and other publicly available information. Although we believe these sources are reliable, we do not guarantee the accuracy or completeness of this information and we have not independently verified this information. In addition, the market and industry data and forecasts that may be included or incorporated by reference in this prospectus, any accompanying prospectus supplement or any applicable free writing prospectus may involve estimates, assumptions and other risks and uncertainties and are subject to change based on various factors, including those discussed under the heading “Risk Factors” contained in this prospectus, the applicable accompanying prospectus supplement and any applicable free writing

the designation and aggregate principal amount of the senior debt securities of such series and their authorized denominations (if other than $2,000 and integral multiples thereof);

the date or dates on which the senior debt securities of such series will mature;

the interest rate or rates, or method of calculation of such rate or rates, on the senior debt securities of such series, and the date from which such interest shall accrue;

the dates on which such interest will be payable or the method by which such dates are to be determined;

the record dates for payment of such interest;

any obligation to redeem or repurchase the senior debt securities of such series, whether pursuant to a sinking fund or analogous provision or at our option or the option of the holder thereof;

the period or periods within which, the price or prices at which, and the terms and conditions upon which, the senior debt securities of such series may be redeemed or repurchased, in whole or in part;

Unless otherwise indicated in the prospectus supplement applicable to the senior debt securities of any series, in any case where the date of payment of the principal of or premium, if any, or interest on the senior debt securities of any series, including the date, if any, fixed for redemption or repurchase of the senior debt securities of such series, shall not be a “business day” ​(as defined below), then payment of principal, premium or interest need not be made on that date at such place but may be made on the next succeeding business day, and no interest shall accrue for the intervening period. A “business day” shall mean a day that is not, in Hartford, Connecticut, a Saturday, Sunday, a legal holiday or a day on which banking institutions are authorized or obligated by law to close.

The senior debt securities will be senior unsecured and unsubordinated indebtedness and will rank equally with all of our existing and future senior unsecured and unsubordinated indebtedness. However, the senior debt securities will be structurally subordinated to the indebtedness of our subsidiaries and effectively subordinated to any secured indebtedness to the extent of the value of the assets securing such indebtedness.

We are obligated to pay reasonable compensation to the trustee and to indemnify the trustee against certain losses, liabilities, expenses and certain taxes incurred by the trustee in connection with its duties relating to the senior debt securities. The trustee’s claims for these payments will generally be senior to those of holders of senior debt securities in respect of all funds collected or held by the trustee.

Unless otherwise indicated in the prospectus supplement applicable to the senior debt securities of any series and except as discussed below, we are not restricted by the indenture from:

incurring any type of indebtedness or other obligation;

paying dividends or making distributions on our capital stock; or

purchasing or redeeming our capital stock.

We are not required under the indenture to maintain any financial ratios or specified levels of net worth or liquidity.

So long as the senior debt securities of any series are outstanding under the indenture, neither we nor any Restricted Subsidiary will, directly or indirectly, issue, incur, create, assume or guarantee any indebtedness secured by a mortgage, security interest, pledge, lien, charge or other encumbrance upon any Principal

Property or upon any shares of capital stock or indebtedness of any Restricted Subsidiary (a “mortgage”), whether such Principal Property, shares or indebtedness are now existing or owned or hereafter created or acquired, unless prior to or at the same time the senior debt securities of such series are equally and ratably secured with or, at our option, prior to such secured indebtedness.

So long as the senior debt securities of any series are outstanding under the indenture, neither we nor any Restricted Subsidiary will enter into any “sale/leaseback transaction” ​(as defined below) with respect to any Principal Property, whether now owned or hereafter acquired by us or any Restricted Subsidiary, unless:

Notwithstanding the restrictions outlined in the preceding paragraphs, we and any Restricted Subsidiary will be permitted to enter into sale/leaseback transactions that would otherwise be subject to such restrictions, without complying with the requirements of clauses (a) and (b) above, if, after giving effect thereto, the aggregate amount of all Attributable Debt with respect to sale/leaseback transactions existing at such time that could not have been entered into except for the provisions described in this paragraph, together with the aggregate amount of all outstanding indebtedness secured by mortgages permitted by any of clauses (1) through (11) under “— Limitation on Liens” above, does not exceed 15% of Consolidated Net Tangible Assets.

We may, without the consent of the holders of any outstanding series of senior debt securities, consolidate with, sell, lease, convey or otherwise transfer all or substantially all of our assets to, or merge with or into, any other person or entity, provided that:

any manufacturing facility (whether now owned or hereafter acquired) that:

The foregoing constitute events of default whatever the reason for any such event of default and whether it is voluntary or involuntary or is effected by operation of any law or pursuant to any judgment, decree or order of any court or any order, rule or regulation of any administrative or governmental body.

If an event of default with respect to the senior debt securities of any series, other than an event of default described in clause (5) above, occurs and is continuing, then the trustee (acting at the request or direction of the holders) or the holders of at least 25% in aggregate principal amount of the outstanding

senior debt securities of such series by notice to us may declare the principal of and accrued but unpaid interest on all the senior debt securities of such series to be due and payable. Upon this declaration, principal of and interest on the senior debt securities of such series will be immediately due and payable. If an event of default described in clause (5) above occurs and is continuing, the principal of and accrued but unpaid interest on all the senior debt securities of such series will become immediately due and payable without any declaration or other act on the part of the trustee or any holders. Under some circumstances, the holders of a majority in aggregate principal amount of the outstanding senior debt securities of such series may rescind any acceleration with respect to the senior debt securities of such series and its consequences.

If an event of default occurs and is continuing, the trustee, in conformity with its duties under the indenture, will be required to exercise all rights or powers under the indenture at the written request or direction of any of the holders, provided the holders provide the trustee with a security or indemnity against the costs, expenses and liabilities that might be incurred by it in compliance with such request or direction. Except to enforce the right to receive payment of principal, premium, if any, or interest when due, no holder of senior debt securities of any series may pursue any remedy with respect to the indenture or the senior debt securities unless:

such holder previously notified the trustee that an event of default is continuing;

the holders of at least 25% in aggregate principal amount of the outstanding senior debt securities of such series requested the trustee to pursue the remedy;

such holders offered the trustee reasonable security or indemnity against the costs, expenses and liabilities that may be incurred by it in compliance with such request;

the trustee has not complied with the holder’s request within 60 days after its receipt of such notice, request and offer of security or indemnity; and

the holders of a majority in principal amount of the outstanding senior debt securities of such series have not given the trustee a direction inconsistent with the request within the 60-day period.

Generally, the holders of a majority in principal amount of the outstanding senior debt securities of a series are given the right to direct the time, method and place of conducting any proceeding for any remedy available to the trustee or of exercising any trust or power conferred on the trustee with respect to the senior debt securities of such series. The trustee, however, may refuse to follow any direction that conflicts with law or the indenture or that the trustee determines is unduly prejudicial to the rights of any other holder of senior debt securities of such series or that would expose the trustee to personal liability.

If a default or event of default with respect to the senior debt securities of a series occurs and is continuing and a responsible officer of the trustee has notice thereof, the trustee must mail to each holder of any debt security of such series notice of the default or event of default within 90 days after it occurs, or if later, after a responsible officer of the trustee has notice of such default or event of default. Except in the case of a default or event of default in the payment of principal, premium, if any, or interest on any debt security of such series, the trustee may withhold notice if the trustee determines in good faith that withholding notice is in the interests of the holders.

In addition, we are required, so long as any of the senior debt securities are outstanding, deliver to the trustee, within 120 days after the end of each fiscal year, an officer’s certificate stating whether or not, to the knowledge of the signers thereof, we are in default in the performance and observance of any of the terms, provisions and conditions of the indenture (without regard to any period of grace or requirement of notice provided hereunder), and if a default or event of default shall have occurred, specifying all such defaults or events of default and the nature and status thereof of which we may have knowledge. We also are required, so long as any of the senior debt securities are outstanding, to deliver to the trustee, within 30 days after becoming aware of any default or event of default, an officer’s certificate specifying such default or event of default and what action we are taking or propose to take with respect thereto.

We and the trustee may amend the indenture as to the senior debt securities of any series with the written consent of the holders of a majority in principal amount of the senior debt securities of such series

then outstanding. Any past default or compliance with any provisions of the indenture or the senior debt securities of such series may be waived with the written consent of the holders of a majority in principal amount of the senior debt securities of such series then outstanding. These consents may be obtained through a tender offer or exchange offer for the senior debt securities of such series.

cure, correct or supplement any ambiguity, omission, defect or inconsistency as to the senior debt securities of such series;

comply with Article V of the indenture, including the assumption by a successor entity of our obligations under the indenture as to the senior debt securities of such series;

provide for uncertificated senior debt securities in addition to or in place of certificated senior debt securities;

add guarantees or collateral security with respect to the senior debt securities of such series;

add to our covenants under the indenture for the benefit of the holders of the senior debt securities of such series or to surrender any right or power conferred upon us as to the senior debt securities of such series;

make any change that does not adversely affect the rights of any holder of senior debt securities of such series in any material respect;

provide for the issuance of and establish the form and terms and conditions of securities of any series as permitted by the indenture;

change or eliminate any of the provisions of the indenture provided that any such change or elimination will become effective only when there is no security outstanding of any series created prior to the execution of such amendment or supplement that is adversely affected by such provision;

comply with any requirement of the SEC regarding qualification of the indenture under the Trust Indenture Act of 1939.

Unless we indicate differently in any applicable prospectus supplement or free writing prospectus, the senior debt securities initially will be issued in book-entry form and represented by one or more global notes or global securities, or, collectively, global securities. The global securities will be deposited with, or on behalf of, The Depository Trust Company, New York, New York, as depositary, or DTC, and registered in the name of Cede & Co., the nominee of DTC. Unless and until it is exchanged for individual certificates evidencing securities under the limited circumstances described below, a global security may not be transferred except as a whole by the depositary to its nominee or by the nominee to the depositary, or by the depositary or its nominee to a successor depositary or to a nominee of the successor depositary.

DTC holds securities that its participants deposit with DTC. DTC also facilitates the settlement among its participants of securities transactions, such as transfers and pledges, in deposited securities through electronic computerized book-entry changes in participants’ accounts, thereby eliminating the need for physical movement of securities certificates. “Direct participants” in DTC include securities brokers and dealers, including underwriters, banks, trust companies, clearing corporations and other organizations. DTC is a wholly-owned subsidiary of The Depository Trust & Clearing Corporation, or DTCC. DTCC is the holding company for DTC, National Securities Clearing Corporation and Fixed Income Clearing Corporation, all of which are registered clearing agencies. DTCC is owned by the users of its regulated subsidiaries. Access to the DTC system is also available to others, which we sometimes refer to as indirect participants, that clear through or maintain a custodial relationship with a direct participant, either directly or indirectly. The rules applicable to DTC and its participants are on file with the SEC.

Purchases of securities under the DTC system must be made by or through direct participants, which will receive a credit for the securities on DTC’s records. The ownership interest of the actual purchaser of a security, which we sometimes refer to as a beneficial owner, is in turn recorded on the direct and indirect participants’ records. Beneficial owners of securities will not receive written confirmation from DTC of their purchases. However, beneficial owners are expected to receive written confirmations providing details of their transactions, as well as periodic statements of their holdings, from the direct or indirect participants through which they purchased securities. Transfers of ownership interests in global securities are to be accomplished by entries made on the books of participants acting on behalf of beneficial owners. Beneficial owners will not receive certificates representing their ownership interests in the global securities, except under the limited circumstances described below.

To facilitate subsequent transfers, all global securities deposited by direct participants with DTC will be registered in the name of DTC’s partnership nominee, Cede & Co., or such other name as may be requested by an authorized representative of DTC. The deposit of securities with DTC and their registration in the name of Cede & Co. or such other nominee will not change the beneficial ownership of the securities. DTC has no knowledge of the actual beneficial owners of the securities. DTC’s records reflect only the identity of the direct participants to whose accounts the securities are credited, which may or may not be the beneficial owners. The participants are responsible for keeping account of their holdings on behalf of their customers.

So long as the securities are in book-entry form, you will receive payments and may transfer securities only through the facilities of the depositary and its direct and indirect participants. We will maintain an office or agency in the location specified in the prospectus supplement for the applicable securities, where notices and demands in respect of the securities and the indenture may be delivered to us and where certificated securities may be surrendered for payment, registration of transfer or exchange.

DTC notifies us that it is unwilling or unable to continue as a depositary for the global security or securities representing such series of securities or if DTC ceases to be a clearing agency registered under the Exchange Act at a time when it is required to be registered and a successor depositary is not appointed within 90 days of the notification to us or of our becoming aware of DTC’s ceasing to be so registered, as the case may be;

an Event of Default has occurred and is continuing with respect to such series of securities,