Jonathan M. Rothberg - Sep 9, 2025 SCHEDULE 13D/A Report for Quantum-Si Inc Class A common stock, par value $0.0001 per share, Class B common stock, par value $0.0001 per share (QSI)

Filing Manager: Jonathan M. Rothberg
Reporting Manager: ROTHBERG JONATHAN M.
Security: Quantum-Si Inc Class A common stock, par value $0.0001 per share, Class B common stock, par value $0.0001 per share
Symbol: QSI
Shares outstanding: 19.9M shares
Disclosed Ownership: 19.9M shares
Ownership: 100%
Form type: SCHEDULE 13D/A
Date filed: 9/11/2025, 05:04 PM
Date of event: Sep 9, 2025
Previous filing: Dec 31, 2024
SEC: View on sec.gov

Reporting Managers (6)

Name	Ownership	Shares Owned	sole voting power	shared voting power	Signature	Title	CIK
ROTHBERG JONATHAN M	7.8%	14.3M	12.1M	2.19M	/s/ Jonathan M. Rothberg	Jonathan M. Rothberg, Ph.D.	0001076352
ROTHBERG JONATHAN M.	100%	19.9M	19.9M	0	/s/ Jonathan M. Rothberg	Jonathan M. Rothberg, Ph.D.
23rd Century Capital LLC	1.05%	1.92M		1.92M	/s/ Jonathan M. Rothberg	Jonathan M. Rothberg, Ph.D., Member
2012 JMR Trust Common, LLC	0%				/s/ Jonathan M. Rothberg	Jonathan M. Rothberg, Ph.D., Manager
4C Holdings I, LLC	90%	17.9M		17.9M	/s/ Jonathan M. Rothberg	Jonathan M. Rothberg, Ph.D., Manager
4C Holdings V, LLC	10%	1.99M		1.99M	/s/ Jonathan M. Rothberg	Jonathan M. Rothberg, Ph.D., Manager