Insider Fitzsimons Reports Ownership Change in Horizon Quantum

TL;DR

**Insider Fitzsimons filed a Form 4 for Horizon Quantum, signaling a change in their stock ownership.**

AI Summary

This Form 4 filing, dated March 24, 2026, indicates that Joseph Francis Fitzsimons, a reporting insider, has filed a statement of changes in beneficial ownership of securities for Horizon Quantum Holdings Ltd. (CIK: 0002088256). While the filing itself doesn't detail specific transactions, it signals that Fitzsimons, an insider, has had a change in their ownership stake as of the report period March 19, 2026. This matters to investors because insider transactions can provide clues about management's confidence in the company's future performance, potentially influencing stock price.

Why It Matters

Insider ownership changes can signal management's view on the company's prospects, which can influence investor sentiment and stock valuation.

Risk Assessment

Risk Level: low — This filing is purely administrative, reporting a change in ownership, and does not inherently indicate a high risk.

Analyst Insight

Investors should monitor subsequent filings or news for Horizon Quantum Holdings Ltd. to understand the nature and size of Fitzsimons Joseph Francis's ownership change, as this filing only indicates a change occurred, not the specifics of the transaction (buy or sell).

Key Players & Entities

• Fitzsimons Joseph Francis (person) — Reporting owner
• Horizon Quantum Holdings Ltd. (company) — Issuer of securities
• 0002122720 (person) — CIK of Fitzsimons Joseph Francis
• 0002088256 (company) — CIK of Horizon Quantum Holdings Ltd.
• 2026-03-24 (date) — Filing Date
• 2026-03-19 (date) — Period of Report

FAQ

Filing Documents

• ownership.html (4)
• ownership.xml (4) — 5KB
• 0001213900-26-033688.txt ( ) — 6KB

From the Filing

SEC FORM 4 SEC Form 4 FORM 4 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940 OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5    Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).    Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10. 1. Name and Address of Reporting Person * Fitzsimons Joseph Francis (Last) (First) (Middle) C/O HORIZON QUANTUM HOLDINGS LTD. 29 MEDIA CIR. #05-22 (Street) SINGAPORE 138565 (City) (State) (Zip) SINGAPORE (Country) 2. Issuer Name and Ticker or Trading Symbol Horizon Quantum Holdings Ltd. [ HQ ] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X Director X 10% Owner X Officer (give title below) Other (specify below) Chief Executive Officer 2a. Foreign Trading Symbol 3. Date of Earliest Transaction (Month/Day/Year) 03/19/2026 6. Individual or Joint/Group Filing (Check Applicable Line) X Form filed by One Reporting Person Form filed by More than One Reporting Person 4. If Amendment, Date of Original Filed (Month/Day/Year) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1. Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Class B Ordinary Shares (1) 03/19/2026 (2) A 19,744,585 A (3) 19,744,585 D Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 6. Date Exercisable and Expiration Date (Month/Day/Year) 7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Explanation of Responses: 1. Each Class B ordinary share, with no par value (the "Class B Ordinary Shares"), is convertible, at any time, in exchange for one Class A ordinary share, with no par value (the "Class A Ordinary Shares"). 2. Class B Ordinary Shares, received on March 19, 2026, upon the closing of business combination (the "Business Combination") contemplated by the Business Combination Agreement, dated as of September 9, 2025 (the "BCA"), by and among Horizon Quantum Computing Pte. Ltd. ("Legacy Horizon"), dMY Squared Technology Group, Inc., Horizon Quantum Holdings Ltd. (the "Company") and certain other parties, as described in the Registration Statement on Form F-4, as amended and supplemented (File No. 333-292737), initially filed with the U.S. Securities and Exchange Commission on January 14, 2026, and declared effective on February 17, 2026. 3. Pursuant to the BCA and as a result of the Business Combination, Dr. Fitzsimons exchanged his then outstanding 8,108,696 ordinary shares of Legacy Horizon for 19,744,585 Class B Ordinary Shares of the Company. /s/ Joseph Fitzsimons 03/24/2026 ** Signature of Reporting Person Date Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. * If the form is filed by more than one reporting person, see Instruction 4 (b)(v). ** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a). Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure. Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number. * Form 4: SEC 1474 (03-26)

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View this 4 filing on SEC EDGAR