ALTC Acq. 如果您正在進行電子投票，請不要退還代理卡。 23157 ALTC Acq.Corp.Proxy Card_REV14-正面 您的投票很重要。請立即投票。 立即-一天24小時、一週7天或通過郵寄投票 通過互聯網投票-快速Easy 摺疊此處·請勿分開·插入提供的信封中 互聯網- www.cstproxyvote.com 使用互聯網投票您的代理。當您訪問上述網站時，確保您的代理卡 可用。按照提示投票 您的股票。 虛擬會議- 如果您計劃參加虛擬在線 特別會議，您需要您的12位數字 控制號碼才能在 特別會議上進行電子投票。要在線參加虛擬特別會議，請對您的代理卡 進行visit： https://www.cstproxy.com/ altcacquisitioncorp/2024. MAIL標記、簽名和註明日期，並將其放入提供的已付郵資的信封 中退回。 您的互聯網投票授權指定的代理人 以相同的方式投票您的股票，就像您 標記、簽署並退回您的代理卡一樣。 通過互聯網以電子方式提交的投票必須在東部時間 晚上11：59之前收到[•] 簽署人在此委任Michael Klein和Jay Taragin(各自為“代表”)為代表， 有權指定一名代理人，在將於美國東部時間 通過https://www.cstproxy.com/altcacquisitioncorp/2024或其任何續會和/或延期舉行的股東特別大會上投票表決簽署人有權投票的股份(“股份”)。該等股份須按本文件背面所列建議投票，並在股東特別大會或其任何延會或延期前適當提出的其他 事項上由受委代表酌情決定。 本委託書所代表的股份在適當籤立時，將按以下籤署股東指示的方式 投票。如果 您退還了一張簽名並註明日期的代理卡，但未就背面的建議給出具體指示 ，則此代理將投票給所有 建議。請在委託書上註明簽名、註明日期並及時退還。 (續並在背面註明、註明日期並簽名) 阿爾特克收購公司股東特別會議委託書。 本委託書是代表董事會徵集的。

23157 ALTC Acq.Corp.Proxy Card_REV14-Back 關於股東特別大會代理材料供應的重要通知 將於[●], 2024 This notice of meeting and the accompanying proxy statement/prospectus/consent solicitation statement are available at https://www.cstproxy.com/altcacquisitioncorp/2024 CONTROL NUMBER Signature______________________________ Signature, if held jointly__________________________________ Date_____________, 2024 When shares are held by joint tenants, both should sign. When signing as attorney, executor, administrator, trustee or guardian, please give full title as such. If a corporation, please sign in full corporate name by president or other authorized officer. If a partnership, please sign in partnership name by an authorized person. Proposal No. 1 — a proposal to (a) approve and adopt that certain Agreement and Plan of Merger and Reorganization, dated July 11, 2023 (the “Merger Agreement”), by and among AltC Acquisition Corp., a Delaware corporation (“AltC”), AltC Merger Sub, Inc., a Delaware corporation and direct wholly-owned subsidiary of AltC (“Merger Sub”), and Oklo Inc., a Delaware corporation (the “Company”), and the related agreements to which AltC is a party and (b) approve the merger of Merger Sub with and into the Company, with the Company surviving such merger as a wholly-owned subsidiary of AltC (the “Merger”), and the other transactions contemplated by the Merger Agreement and the related agreements to which AltC is a party (the “Transactions” or the “business combination” and, such proposal, the “business combination proposal”). Proposal No. 2 — a proposal to approve and adopt the proposed second amended and restated certificate of incorporation (the “second amended and restated certificate of incorporation”) of the post-closing company (the “Post-Closing Company”) in the form attached to the accompanying proxy statement/ prospectus/consent solicitation statement as Annex B (the “charter proposal”). Proposal No. 3 — a proposal to approve, on a non-binding advisory basis, certain governance provisions in the second amended and restated certificate of incorporation, presented separately in accordance with the United States Securities and Exchange Commission requirements (the “governance proposal”). Proposal No. 3A: a proposal to amend AltC’s amended and restated certificate of incorporation to restructure the capitalization of AltC such that (i) each share of Class A common stock of AltC, par value $0.0001 per share (“AltC Class A common stock”), issued and outstanding immediately prior to the date and time that the Merger becomes effective (the “Effective Time”) will remain outstanding as one (1) share of Class A common stock of the Post-Closing Company, par value $0.0001 per share (“Post-Closing Company Class A Common Stock”), and (ii) each share of Class B common stock of AltC, par value $0.0001 per share (“Class B common stock”), issued and outstanding immediately prior to the Effective Time will be reclassified on a one-for-one basis as one (1) share of Post-Closing Company Class A Common Stock. Proposal No. 3B: a proposal to amend AltC’s amended and restated certificate of incorporation to remove (i) the exclusive right of holders of Class B common stock to elect and remove directors of AltC, and instead require the approval by (x) a plurality of the votes cast by the stockholders present in person or represented by proxy and entitled to vote generally on the election of directors, to elect directors of the Post-Closing Company and (y) the affirmative vote of holders of at least a majority in voting power of the outstanding shares of capital stock of the Post-Closing Company entitled to vote generally in the election of directors, voting together as a single class, to remove directors from the Post-Closing Company; and (ii) stockholders’ ability to remove a director without cause. Proposal No. 3C: a proposal to amend AltC’s amended and restated certificate of incorporation to require the approval of the affirmative vote of holders of at least 66 2/3% in voting power of the outstanding shares of the capital stock of the Post-Closing Company entitled to vote thereon to approve changes to the Post-Closing Company’s bylaws and to amend or repeal any provisions inconsistent with certain sections of the second amended and restated certificate of incorporation. Proposal No. 3D: a proposal to amend AltC’s amended and restated certificate of incorporation to remove the requirement that a business combination or similar acquisition of the Post-Closing Company must be approved by at least 66 2/3% in voting power of the outstanding shares of capital stock of the Post-Closing Company entitled to vote thereon. Proposal No. 4 — a proposal to approve and adopt the Oklo Inc. 2024 Equity Incentive Plan (the “Incentive Plan”) in the form attached to the accompanying proxy statement/ prospectus/consent solicitation statement as Annex F, and the material terms thereof, including the authorization of the initial share reserve thereunder (the “incentive plan proposal”). Proposal No. 5 — a proposal to approve and adopt the Oklo Inc. 2024 Employee Stock Purchase Plan (the “ESPP”) in the form attached to the accompanying proxy statement/prospectus/consent solicitation statement as Annex G, and the material terms thereof, including the authorization of the initial share reserve thereunder (the “ESPP proposal”). Proposal No. 6 — a proposal to elect seven directors to serve staggered terms on the Post-Closing Company’s board of directors following the consummation of the business combination until immediately following the date of the 2025, 2026 and 2027 annual stockholder meetings, or in each case until their respective successors are duly elected and qualified, or until their earlier resignation, removal or death (the “director election proposal”). Nominee Class Lieutenant General (Ret.) John Jansen I Michael Klein I Sam Altman II Caroline Cochran II Richard W. Kinzley II Jacob DeWitte III Chris Wright III To withhold authority to vote for any individual nominee(s), mark “FOR ALL EXCEPT” and write the name(s) of the nominee(s) on the line below _________________________________________________________________ Proposal No. 7 - a proposal to approve, for purposes of complying with the applicable provisions of Section 312.03 of the New York Stock Exchange’s (the “NYSE”) Listed Company Manual, the issuance of shares of Post-Closing Company Class A Common Stock, including the approval of (a) the issuance of more than 20% of AltC’s issued and outstanding shares of common stock in connection with the business combination and (b) the issuance of shares of AltC Class A common stock (i) to one or more Related Parties (as defined in Section 312.03 of the NYSE’s Listed Company Manual) in connection with the Transactions and (ii) in connection with the acquisition of a company in which a Related Party may have a 5% or greater interest in or in the consideration to be paid in connection with such acquisition (the “NYSE proposal”). Proposal No. 8 — a proposal to adjourn the special meeting to a later date or dates, if necessary, to permit further solicitation and vote of proxies in the event that there are insufficient votes for, or otherwise in connection with, the approval of the business combination proposal, the charter proposal, the governance proposal, the incentive plan proposal, the ESPP proposal, the director election proposal or the NYSE proposal (the “adjournment proposal”). PROXY CARD THE BOARD OF DIRECTORS UNANIMOUSLY (OF THOSE WHO VOTED) RECOMMENDS A VOTE “FOR” ALL PROPOSALS. Please mark your votes like this X FOR ALL WITHHOLD ALL FOR ALL EXCEPT FOR AGAINST ABSTAIN FOR AGAINST ABSTAIN FOR AGAINST ABSTAIN FOR AGAINST ABSTAIN FOR AGAINST ABSTAIN FOR AGAINST ABSTAIN FOR AGAINST ABSTAIN FOR AGAINST ABSTAIN FOR AGAINST ABSTAIN FOR AGAINST ABSTAIN