Filed Pursuant to Rule 424(b)(3)
Registration No. 333-294802
PROSPECTUS SUPPLEMENT NO. 4
(To Prospectus dated
April 9, 2026)
Up to 10,425,000 Shares of Common Stock Issuable Upon Exercise of Warrants
and
Up to 121,829,432
Shares of Common Stock
and
Up to 75,000 Private Warrants
Offered by the Selling Securityholders
This prospectus supplement supplements the prospectus dated April 9, 2026 (as supplemented, the “Prospectus”), which
forms a part of our registration statement on Form S-1 (No. 333-294802). This prospectus supplement is being filed to update and supplement the
information in the Prospectus solely for the purpose of including Selling Securityholders (as defined below) who have acquired shares of our Common Stock (as defined below) from certain existing selling securityholders previously named in the
Prospectus.
The Prospectus and this prospectus supplement relate to the issuance by us of an aggregate of up to 10,425,000 shares of our
common stock, $0.0001 par value per share (the “Common Stock”), which consists of (i) up to 75,000 shares of Common Stock that are issuable upon the exercise of warrants (the “Private Warrants”) originally
issued in a private placement to Churchill Sponsor X, LLC (the “Sponsor”) in connection with the initial public offering of Churchill Capital Corp X (“CCX”) and (ii) up to 10,350,000 shares of Common Stock
that are issuable upon the exercise of 10,350,000 warrants (the “Public Warrants” and with the Private Warrants, the “Warrants”) originally issued in the initial public offering of CCX. We will receive the
proceeds from any exercise of any Warrants for cash.
The Prospectus and this prospectus supplement also relate to the offer and sale from
time to time by the selling securityholders named in the Prospectus or their permitted transferees (the “Selling Securityholders”) of (i) up to 121,829,432 shares of Common Stock issued in connection with the Business
Combination (as defined below), consisting of (a) up to 12,654,760 shares of Common Stock issued in connection with private placements pursuant to subscription agreements entered into on September 8, 2025 (the “PIPE
Shares”), (b) up to 10,350,000 shares of Common Stock originally issued to the Sponsor (the “Founder Shares”), including 1,500,000 Founder Shares that were unvested as of the Closing (as defined below) and will re-vest upon the occurrence of the Triggering Event (as defined in the Sponsor Agreement), (c) up to 300,000 shares of Common Stock originally issued to the Sponsor in a private placement (the “CCX Private
Placement Shares”) in connection with the initial public offering of CCX, (d) up to 98,449,672 shares of Common Stock issued to former securityholders of ColdQuanta, Inc. (d/b/a Infleqtion) (the “Legacy Infleqtion
Holders”) in connection with the Business Combination registrable pursuant to that certain Amended and Restated Registration Rights Agreement, dated as of September 8, 2025, between us and the Selling Securityholders granting such
holders registration rights with respect to such shares, and (e) up to 75,000 shares of Common Stock issuable upon the exercise of the Private Warrants, and (ii) up to 75,000 Private Warrants.
We will not receive any proceeds from the sale of shares of Common Stock or Warrants by the Selling Securityholders pursuant to the
Prospectus. We will receive proceeds from the exercise of the Warrants for cash, but not from the sale of the shares of Common Stock issuable upon such exercise.