Tan Si-Hui 4

What Happened
Tan Si‑Hui, Chief Science Officer of Horizon Quantum Holdings Ltd., was granted/acquired 500,000 stock options on March 19, 2026. Each option is exercisable for 2.43499 Class A Ordinary Shares at an exercise price of $0.15 per share, meaning the options cover approximately 1,217,495 underlying Class A shares. Exercising all options would require about $182,624.25 in cash (1,217,495 × $0.15). The options were received as substitute awards in connection with the closing of the business combination and are fully vested and exercisable.

Key Details

• Transaction date: 2026-03-19 (reported on Form 4 filed 2026-03-25).
• Transaction type/code: Award/Grant (A).
• Instrument: 500,000 stock options, each exercisable for 2.43499 Class A shares at $0.15 per share.
• Underlying shares if fully exercised: ~1,217,495 Class A Ordinary Shares.
• Cash required to exercise all options: ~$182,624.25.
• Vesting/status: Options are fully vested and exercisable (F3).
• Origin: Options were exchanged for Legacy Horizon options as part of the March 19, 2026 business combination (F2, F4).
• Shares owned after transaction: Not specified in this Form 4.
• Filing timeliness: Form 4 was filed March 25 for a March 19 transaction — filed after the typical two-business-day deadline.

Context
These entries reflect a substitute/options award tied to the closing of a merger (not an open‑market buy or sale). No exercise, sale, or cashless transaction was reported here — this filing records the exchange/grant of option awards and confirms they are fully vested and exercisable. Awards exchanged as part of business combinations are common and do not by themselves signal insider buying or selling.