[Form 4] Quantum-Si Inc Insider Trading Activity

Rhea-AI Filing Summary

Quantum-Si (QSI) director and 10% owner Jonathan M. Rothberg reported the sale of 26,095 shares of Class A common stock on 10/16/2025 (transaction code S). The sale was executed pursuant to a Rule 10b5-1 trading plan established on September 13, 2024 and described as part of estate planning.

The filing states a weighted average price of $3.07 per share, with shares sold between $3.07 and $3.09. Following the transaction, beneficial ownership includes 2,568,443 Class A shares held directly and additional indirect holdings through various entities, including 1,904,866 Class A by NVR TR, LLC. Indirect holdings also include Class B common stock of 17,943,750 shares by 4C Holdings I, LLC and 1,993,750 shares by 4C Holdings V, LLC. The filing notes prior estate-planning distributions among affiliated trusts and that Dr. Rothberg disclaims beneficial ownership of shares held by his spouse and by 23rd Century Capital LLC.

10/17/2025 - 07:05 PM

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

X

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

ROTHBERG JONATHAN M

(Last) (First) (Middle)

C/O QUANTUM-SI INCORPORATED

29 BUSINESS PARK DRIVE

(Street)

BRANFORD CT 06405

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Quantum-Si Inc [ QSI ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
10/16/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Class A Common Stock	10/16/2025		S		26,095(1)	D	$3.07(2)	1,904,866(3)	I	By NVR TR, LLC(4)
Class A Common Stock								1,930,960(3)	I	By JNR TR, LLC(4)
Class A Common Stock								1,930,960(3)	I	By GBR TR, LLC(4)
Class A Common Stock								1,930,960(3)	I	By EJR TR, LLC(4)
Class A Common Stock								1,250,000	I	By JAR TR, LLC(4)
Class A Common Stock								2,568,443	D
Class A Common Stock								1,917,067	I	By 23rd Century Capital LLC(4)
Class A Common Stock								273,422	I	By Bonnie E Gould Rothberg MD(4)
Class B Common Stock								17,943,750	I	By 4C Holdings I, LLC(4)
Class B Common Stock								1,993,750	I	By 4C Holdings V, LLC(4)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. This sale was effected in connection with estate planning pursuant to a 10b5-1 trading plan established by Dr. Rothberg on September 13, 2024.

2. Represents the weighted average sales price per share. The shares sold at prices ranging from $3.07 to $3.09 per share. Full information regarding the number of shares sold at each price shall be provided upon request to the staff of the U.S. Securities and Exchange Commission, the Issuer, or a security holder of the Issuer.

3. Includes additional shares of Class A common stock previously held by 2012 JMR Trust Common, LLC that were distributed for estate planning purposes to NVR TR, LLC, JNR TR, LLC, GBR TR, LLC and EJR TR, LLC.

4. Dr. Rothberg is the sole manager of 4C Holdings I, LLC, 4C Holdings V, LLC, 2012 JMR Trust Common, LLC, NVR TR, LLC, JNR TR, LLC, GBR TR, LLC, EJR TR, LLC and JAR TR, LLC and. Dr. Rothberg is the spouse of Bonnie E. Gould Rothberg MD and Dr. Rothberg's son is the manager of 23rd Century Capital LLC. Dr. Rothberg disclaims beneficial ownership of the shares held by his spouse and 23rd Century Capital LLC.

	/s/ Jonathan M. Rothberg, Ph.D.	10/17/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What did QSI insider Jonathan M. Rothberg report on Form 4?

He reported selling 26,095 Class A shares on 10/16/2025 under a Rule 10b5-1 plan.

At what price were the QSI shares sold?

The filing lists a weighted average price of $3.07 per share, with a range of $3.07–$3.09.

What is Rothberg’s relationship to Quantum-Si (QSI)?

He is a Director and a 10% Owner of the company.

How many QSI shares does Rothberg hold after the transaction?

Holdings include 2,568,443 Class A shares directly and indirect positions such as 1,904,866 Class A via NVR TR, LLC.

Does Rothberg hold QSI Class B shares?

Yes. Indirect holdings include 17,943,750 Class B via 4C Holdings I, LLC and 1,993,750 Class B via 4C Holdings V, LLC.

Was the sale part of a pre-arranged plan?

Yes. It was executed under a 10b5-1 trading plan established on September 13, 2024 for estate planning.

Are any holdings disclaimed?

Yes. He disclaims beneficial ownership of shares held by his spouse and by 23rd Century Capital LLC.