AMG Pantheon Master Fund SC TO-IIssuer tender offer statement

Check the box if the filing relates solely to preliminary communications made before commencement of a tender offer.

third-party tender offer subject to Rule 14d-1.

issuer tender offer subject to Rule 13e-4.

going-private transaction subject to Rule 13e-3.

amendment to Schedule 13D under Rule 13d-2.

Summary Term Sheet.

Subject Company Information.

The name of the issuer is AMG Pantheon Master Fund, LLC (the “Fund”). The Fund is registered under the Investment Company Act of 1940, as amended (the “1940 Act”), as a closed-end, non-diversified management investment company. It is organized as a Delaware limited liability company. The principal office of the Fund is located at 680 Washington Boulevard, Suite 500, Stamford, Connecticut 06901 and the telephone number is (877) 355-1566.

The title of the securities that are the subject of the offer to repurchase and the related Letter of Transmittal (“Offer to Repurchase” and the tender offer made thereby, the “Offer”) are units of beneficial interest (“Units”) or portions thereof. As of the close of business on October 31, 2024, there were approximately 172,414,051 Units outstanding. Subject to the conditions set forth in the Offer to Repurchase, the Fund will repurchase up to 8,620,703 Units that are tendered by holders of the Fund’s Units (“Members”) and not withdrawn as described in the Offer to Repurchase (the “Offer Amount”). The Units subject to the Offer represent approximately 5% of the Fund’s Units outstanding as of October 31, 2024.

Units are not traded in any market, and any transfer thereof is strictly limited by the terms of the Fund’s Limited Liability Company Agreement, as amended (the “LLC Agreement”).

Identity and Background of Filing Person.

The Fund is tendering for its own Units. The information required by this Item is set forth in Item 2(a) above. Pantheon Ventures (US) LP (“Pantheon”) serves as the investment adviser for the Fund. Pantheon is located at 555 California Street, Suite 3450, San Francisco, California 94104 and its telephone number is (415) 249-6200. The members of the Fund’s Board of Directors (the “Board”) are Kurt Keilhacker, Eric Rakowski, Victoria Sassine and Garret W. Weston (each, a “Director”). The officers of the Fund are Keitha L. Kinne, Thomas G. Disbrow, Susan Long McAndrews, Mark J. Duggan, Patrick J. Spellman, and John A. Starace (each, an “Officer”). The Directors and Officers may be reached at the Fund’s business address and phone number set forth in Item 2(a) above. AMG Pantheon Fund, LLC (the “Feeder Fund”) and the Fund are organized in what is commonly referred to as a “master-feeder” structure.

Not applicable.

Terms of the Transaction.

Subject to the conditions set forth in the Offer to Repurchase, the Fund will repurchase up to 8,620,703 Units that are tendered by Members by 11:59 p.m., Eastern Time, on January 28, 2025 and not withdrawn as described in Item 4(a)(1)(vi).

The purchase price of a Unit (or portion thereof) tendered will be its net asset value as of the close of business on March 31, 2025 or a later date determined by the Fund if the Offer is extended (in each case, the “Valuation Date”), upon the terms and subject to the conditions set forth in the Offer to Repurchase. Reference is made to the Cover Page, Section 2 “Offer to Repurchase and Price” and Section 6 “Purchases and Payment” of the Offer to Repurchase, which are incorporated herein by reference.

The Offer is scheduled to expire on January 28, 2025, unless extended. Reference is made to the Cover Page, Summary Term Sheet, Section 2 “Offer to Repurchase and Price”, Section 4 “Procedures for Tenders” and Section 5 “Withdrawal Rights” of the Offer to Repurchase, which are incorporated herein by reference.

Not applicable.

Reference is made to the Cover Page, Summary Term Sheet, Section 3 “Amount of Tender” and Section 7 “Certain Conditions of the Offer” of the Offer to Repurchase, which are incorporated herein by reference.

Reference is made to Cover Page, Summary Term Sheet and Section 5 “Withdrawal Rights” of the Offer to Repurchase, which is incorporated herein by reference.

Reference is made to the Cover Page, Section 4 “Procedure for Tenders” and Section 5 “Withdrawal Rights” of the Offer to Repurchase, which are incorporated herein by reference. All Members tendering Units should carefully review their Letter of Transmittal and follow the delivery instructions therein.

Reference is made to Section 4 “Procedure for Tenders” and Section 6 “Purchases and Payment” of the Offer to Repurchase, which are incorporated herein by reference.

Reference is made to the Cover Page, Summary Term Sheet, Section 3 “Amount of Tender,” and Section 6 “Purchases and Payment” of the Offer to Repurchase, which are incorporated herein by reference.

Reference is made to Section 1 “Background and Purpose of the Offer” of the Offer to Repurchase, which is incorporated herein by reference.

Not applicable.

Reference is made to Section 9 “Certain U.S. Federal Income Tax Consequences” of the Offer to Repurchase, which is incorporated herein by reference.

Not applicable.

Any Units to be purchased from any officer, Director or affiliate of the Fund will be on the same terms and conditions as any other purchase of Units.

Past Contracts, Transactions, Negotiations and Agreements.

Not applicable.

The Board has the discretion to determine whether the Fund will purchase Units from Members from time to time pursuant to written tenders. Pantheon expects that it will recommend to the Board that the Fund purchase Units from Members quarterly. However, the Fund is not required to conduct tender offers. The Fund does not know of any other contract, agreement, arrangement, understanding or relationship, whether contingent or otherwise or whether or not legally enforceable, between the Fund, any of the Fund’s Officers or Directors, any person controlling the Fund, or any executive officer or director of any corporation ultimately in control of the Fund and any person with respect to any securities of the Fund (including any contract, agreement, arrangement, understanding or relationship concerning the transfer or the voting of any such securities, joint ventures, loan or option arrangements, puts or calls, guarantees of loans, guarantees against loss, or the giving or withholding of proxies, consents or authorizations). The Fund’s LLC Agreement provides that, if a Member submits to the Fund a written request to commence a repurchase offer and the Fund does not, within two years from the date of such written request, commence a repurchase offer for at least 5% of the net assets of the Fund, the Fund promptly will thereafter offer to all then Members the opportunity to contribute their Units to a special purpose vehicle (an “SPV”) to be registered under the 1940 Act or exempt from such registration and having the investment objective to liquidate at least 90% of its assets within three full fiscal years of such contribution. Any such offer to contribute will be made pursuant to an offering registered under the Securities Act of 1933, as amended, or pursuant to an offering exempt from such registration. Any such SPV would not bear any investment advisory or investment management fees after the three fiscal year period.

Purposes of the Transaction and Plans or Proposals.

Reference is made to Section 1 “Background and Purpose of the Offer” of the Offer to Repurchase, which is incorporated herein by reference.

Reference is made to Section 8 “Certain Information About the Fund” of the Offer to Repurchase, which is incorporated herein by reference. Because Units are not traded in any market, subsections (6), (7), and (8) of Regulation M-A §229.1006(c) are not applicable to the Fund.

Source and Amount of Funds or Other Consideration.

Reference is made to Summary Term Sheet and Section 6 “Purchases and Payment” of the Offer to Repurchase, which is incorporated herein by reference.

Interest in Securities of the Issuer.

Based on the number of Units outstanding as of October 31, 2024, the following persons (the named individuals being the Directors) own the number of Units indicated in the below table.

Reference is made to Section 8 “Certain Information About the Fund” of the Offer to Repurchase, which is incorporated herein by reference. Other than the issuance of Units by the Fund in the ordinary course of business, there have been no transactions in the Fund’s Units effected during the past 60 days by the Fund, Pantheon, or any Director or officer of the Fund, or any person controlling the Fund or Pantheon, or by the Feeder Fund or any Director or officer of the Feeder Fund.

Persons/Assets, Retained, Employed, Compensated or Used.

No persons have been employed, retained or are to be compensated by the Fund to make solicitations or recommendations in connection with the Offer to Repurchase.

Financial Statements.

The unaudited semi-annual financial statements of the Fund dated September 30, 2024 and the schedule of investments of the Fund dated September 30, 2024, both filed with the SEC on EDGAR on Form N-CSR on December 9, 2024, are incorporated by reference. The Fund will prepare and transmit to Members the audited annual financial statements of the Fund and the schedule of investments of the Fund within 60 days after the close of the period for which the report is being made, or as otherwise required by the 1940 Act.

Not applicable.

Additional Information.

None.

None.

Not applicable.

None.

None.

The Offer to Repurchase, attached hereto as Exhibit (a)(1)(ii), is incorporated herein by reference in its entirety.

Exhibits.

Cover Letter to Offer to Repurchase.

Offer to Repurchase.

Form of Letter of Transmittal.

Form of Letter from the Fund to Members in Connection with the Fund’s Acceptance of Units.

Form of Notice of Withdrawal of Tender.

Not applicable.

None.

None.

Not applicable.

Not applicable.