Transaction Details

Footnotes

Each stock option is exercisable for 2.43499 Class A Ordinary Shares of Horizon Quantum Holdings Ltd. (the "Company") at a price per share of $5.13. | Stock options received as part of the 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., 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. Upon the closing of the Business Combination on March 19, 2026, Mr. Gould's stock options exercisable for Legacy Horizon ordinary shares awarded by Legacy Horizon were exchanged for substitute stock option awards of the Company of an equivalent economic value, which are subject to a vesting schedule as further detailed in footnote 3. | The stock options held by Mr. Gould are subject to Mr. Gould's continued employment with the Company and vest quarterly in 16 equal installments, beginning on August 15, 2025. As of March 24, 2026, 35,662 stock options are fully vested and exercisable, with the remaining 249,638 stock options vesting in accordance with the forgoing schedule. | Pursuant to the BCA and as a result of the closing of the Business Combination, Mr. Gould's 285,300 Legacy Horizon stock options were exchanged for 285,300 stock options of the Company of an equivalent economic value, with an exercise price per Class A Ordinary Share of $5.13.