Si-Hui Tan

CIK: 0002120880

Transaction Breakdown

Open Market Buys (P)0 (0.0%)

High conviction signal

Open Market Sales (S)0 (0.0%)

Position reduction

Option Exercises (M)1 (16.7%)

Derivative conversions

Awards (A)4 (66.7%)

Compensation grants

Other (G, F, J, C, D, …)1 (16.7%)

Gifts, tax withholding, conversions, dispositions to the issuer and other codes

Companies & Roles (1)

Horizon Quantum Holdings Ltd.

Officer

Discretionary Trading P&L

Holdings

Transaction History (6 total)

HQ
Horizon Quantum Holdings Ltd.
Sep 12, 2026
Exercise(M)
Direct
5.7K shares-
HQ
Horizon Quantum Holdings Ltd.
Sep 12, 2026
Disposition(D)
Direct
3K shares at avg. $15.22$46K
HQ
Horizon Quantum Holdings Ltd.
Aug 20, 2026
Award(A)
Indirect
3.6K shares-
HQ
Horizon Quantum Holdings Ltd.
Jun 12, 2026
Award(A)
Restricted Stock Unit
Direct
91.7K shares-
HQ
Horizon Quantum Holdings Ltd.
Mar 19, 2026
Award(A)
Stock Option (Right to Buy)
Indirect
55K shares-
HQ
Horizon Quantum Holdings Ltd.
Mar 19, 2026
Award(A)
Stock Option (Right to Buy)
Direct
500K shares-

		Type	Shares	Price		Ownership
Sep 12, 2026	HQ Horizon Quantum Holdings Ltd.	Exercise(M)	5,728	-	$0	Direct
Sep 12, 2026	HQ Horizon Quantum Holdings Ltd.	Disposition(D)	2,991	$15.22	$45,523	Direct
Aug 20, 2026	HQ Horizon Quantum Holdings Ltd.	Award(A)	3,600	-	$0	Indirect
Jun 12, 2026	HQ Horizon Quantum Holdings Ltd.	Award(A) Restricted Stock Unit	91,659	-	-	Direct
Mar 19, 2026	HQ Horizon Quantum Holdings Ltd.	Award(A) Stock Option (Right to Buy)	55,000	-	-	Indirect
Mar 19, 2026	HQ Horizon Quantum Holdings Ltd.	Award(A) Stock Option (Right to Buy)	500,000	-	-	Direct

1-6 of 6 transactions

About Tan Si-Hui

Tan Si-Hui (SEC CIK 0002120880) files insider reports with the SEC as Chief Science Officer of Horizon Quantum Holdings Ltd. (HQ).

Signal8 holds 3 ownership filings by Tan Si-Hui (1 Form 3, 2 Form 4), filed between Mar 19, 2026 and Sep 15, 2026. Those filings report 6 transactions, from Mar 19, 2026 to Sep 12, 2026. Signal8's Form 4 history starts in Sep 2024.

The business address on Tan Si-Hui's filings is in SINGAPORE.

Recent filings by Tan Si-Hui

Sep 12, 2026: Option exercise of HQ shares (Form 4, code M).
Sep 12, 2026: Disposition to issuer transaction of HQ shares (Form 4, code D).
Aug 20, 2026: Grant or award of HQ shares (Form 4, code A).
Jun 12, 2026: Grant or award of HQ derivative securities (Form 4, code A).
Mar 19, 2026: Grants or awards of HQ derivative securities (2 lines, Form 4, code A).

Other insiders filing for Horizon Quantum Holdings Ltd. (HQ)

Fitzsimons Catherine Michele, CLO and CCO
Chew Qian Yi Amanda, Chief Product Officer
Gould Greg, Chief Financial Officer
Fitzsimons Joseph Francis, Chief Executive Officer
Turner Jill Ann, Director
Lambert Danielle, Director

How to read Form 4 transaction codes