When QNT insiders can sell

LLC, we and they will not, subject to certain exceptions, during the period ending 180 days after the date of this prospectus offer, sell, contract to sell, pledge, grant any option to purchase, lend or otherwise dispose of any shares of our Class A common stock, or any options or warrants to purchase any shares of our Class A common 217 Table of Contents stock, or any securities convertible into, or exchangeable for, or that represent the right to receive, shares of our Class A common stock or engage in any hedging or other transaction or arrangement (including, without limitation, any short sale or the purchase or sale of, or entry i…

Class A common stock to be outstanding immediately after this offering 32,862,895 shares (or 37,062,895 shares if the underwriters exercise their option to purchase additional shares of Class A common stock in full). Class B common stock to be outstanding immediately after this offering 228,107,842 shares. Common Units to be held by us immediately after this offering 32,862,895 Common Units, representing a 12.6% economic interest in Quantinuum Holdings (or 37,062,895 Common Units, representing a 14.0% economic interest in Quantinuum Holdings, if the underwriters exercise their option to purchase additional shares of Class A common stock in full).

…on shall become a publicly available registration statement during the restricted period or (viii) the facilitation of the establishment of a trading plan on behalf of a stockholder, officer or director pursuant to Rule 10b5-1 under the Exchange Act for the transfer of shares of common stock provided that (a) such plans do not provide for the transfer of shares of common stock during the restricted period and (b) no filing by any party under the Exchange Act or other public announcement shall be required or made voluntarily in connection with such trading plan (other than the required disclosure on Form 10-Q or Form 10-K, as applica…

…between the underwriters and the lock-up parties do not apply, subject in certain cases to various conditions, to certain transactions, including (a) transfers, distributions or surrenders of lock-up securities (i) as a bona fide gift or gifts, or for bona fide estate planning purposes, including, without limitation to charitable organizations or 226 Table of Contents educational institutions (ii) to any immediate family member of the lock-up parties (iii) by will, other testamentary document or intestacy (iv) to any trust for the direct or indirect benefit of the lock-up party or the immediate family member of the lock-up party, or…

…o be a participant, in which (i) the amount involved exceeded or will exceed $120,000 and (ii) any of our directors, executive officers, or holders of more than 5% of our capital stock, or any affiliate or member of the immediate family of the foregoing persons or entities, had or will have a direct or indirect material interest, other than compensation and other arrangements that are described under "Executive and Director Compensation." We believe the terms obtained or consideration that we paid or received, as applicable, in connection with the transactions described below were comparable to terms available or the amounts that we would pay or receive, as applicable, in arm's-length transactions.

See "Underwriting—Directed Share Program." Quantinuum Inc. has granted the underwriters the option for a period of 30 days to purchase up to an additional 4,200,000 shares of Class A common stock at the initial public offering price less underwriting discounts and commissions. The Securities and Exchange Commission and state securities regulators have not approved or disapproved of these securities or determined if this prospectus is truthful or complete.

(i) shares subject to stock appreciation rights, or SARs, that are not issued in connection with the stock settlement of the SAR on exercise, and (ii) shares purchased on the open market with the cash proceeds from the exercise of options. Awards granted under the 2026 Plan upon the assumption of, or in substitution for, awards authorized or outstanding under a qualifying equity plan maintained by an entity with which we enter into a merger or similar corporate transaction will not reduce the shares available for grant under the 2026 Plan but will count against the maximum number of shares that may be issued upon the exercise of ISOs.