Form 4 for HQ Horizon Quantum Holdings Ltd.

Accepted 2026-03-20 00:00:00 ET · period of report 2026-03-19 · accession 0001829126-26-002587 · SEC index · Original document

Summary rows

Aggregated the way they appear in lists: one row per insider, transaction code and security table.

X	Filed	Traded	Ticker	Insider	Title	Type	Price	Qty	Owned	ΔOwn	Value
DI	2026-03-20	2026-03-19	HQ	You Harry L.	Dir, 10%	A - Grant	—	+1.16M	1.16M	New	—
DI	2026-03-20	2026-03-19	HQ	You Harry L.	Dir, 10%	A - Grant	—	+2.88M	2.88M	New	—

Purchase Sale Sale after option exercise All abbreviations

Every reported transaction

#	Table	Security	Date	Code	A/D	Shares	Price	Owned after	Own	Exercise / expiry	Underlying	Footnotes
1	Common	Class A Ordinary Shares	2026-03-19	A	A	1,163,484	—	1,163,484	I See footnote	—	—	(F1) In connection with the closing of the business combination (the "Business Combination") among Horizon Quantum Holdings Ltd. (the "Issuer"), Horizon Quantum Computing Pte. Ltd. ("Horizon"), and dMY Squared Technology Group, Inc. ("DMY"), these Class A ordinary shares of the Issuer were issued pursuant to the terms of the Business Combination Agreement, dated as of September 9, 2025, by and among the Issuer, Horizon, and DMY (the "Business Combination Agreement") upon the exchange of 1,163,484 shares of Class A common stock of DMY. On the effective date of the Business Combination, the closing price of DMY's Class A common stock was $13.50. (F3) dMY Squared Sponsor, LLC (the "Sponsor") Sponsor is the record holder of the securities reported herein. Harry L. You is the managing member of the Sponsor and has voting and investment discretion with respect to the securities held of record by the Sponsor. Each of the Sponsor and Mr. You is a "Reporting Person" and may be deemed to beneficially own the securities reported herein; however, each Reporting Person disclaims beneficial ownership of the securities reported herein, except to the extent of such Reporting Person's pecuniary interest therein. Solely for purposes of Section 16 of the Exchange Act, each Reporting Person may be deemed a "director by deputization".
2	Derivative	Warrants	2026-03-19	A	A	2,884,660	—	2,884,660	I See footnote	$11.50 · 2026-04-18 to 2031-03-19	2,884,660 Class A Ordinary Shares	(F2) In connection with the closing of the Business Combination, these warrants of the Issuer were issued pursuant to the terms of the Business Combination Agreement upon the exchange of 2,884,660 warrants of DMY. On the effective date of the Business Combination, the closing price of DMY's warrants was $2.69. (F3) dMY Squared Sponsor, LLC (the "Sponsor") Sponsor is the record holder of the securities reported herein. Harry L. You is the managing member of the Sponsor and has voting and investment discretion with respect to the securities held of record by the Sponsor. Each of the Sponsor and Mr. You is a "Reporting Person" and may be deemed to beneficially own the securities reported herein; however, each Reporting Person disclaims beneficial ownership of the securities reported herein, except to the extent of such Reporting Person's pecuniary interest therein. Solely for purposes of Section 16 of the Exchange Act, each Reporting Person may be deemed a "director by deputization".