Quantum-Si CFO sells 7,665 shares over two days

Both transactions were mandatory tax-withholding sales tied to vesting of previously granted restricted stock units.

Rhea-AI Filing Summary

Quantum-Si Inc. (QSI) Chief Financial Officer Jeffry R. Keyes reported selling 5,172 Class A common shares on September 21, 2026, at a weighted average price of $0.7558 per share, and 2,493 shares on September 22 at $0.7608 per share. Both sales were made under a mandatory sell-to-cover provision for required federal, state and local withholding taxes tied to vesting of previously granted restricted stock units. The provision could not be altered, and no Rule 10b5-1 plan is reported.

Insider Trade Summary

Net Seller: 7,665 shares

Net Sell 2 txns

Insider Keyes Jeffry R.

Role Chief Financial Officer

Sold 7,665 shs ($6K)

Type	Security	Shares	Price	Value
Sale	Class A Common Stock F1, F3	2,493	$0.7608	$2K
Sale	Class A Common Stock F1, F2	5,172	$0.7558	$4K

Holdings After Transaction: Class A Common Stock — 1,716,684 shares (Direct)

Footnotes (3)

1. F1. Represents shares sold pursuant to a mandatory Quantum-Si sell-to-cover provision for required federal, state and local withholding taxes in connection with the vesting of previously granted restricted stock units. Individual is not able to alter this mandatory sell-to-cover provision that is enacted at the grant date of the related restricted stock unit award.
2. F2. Represents the weighted average sales price per share. The shares sold at prices ranging from $0.75 to $0.762 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. F3. Represents the weighted average sales price per share. The shares sold at prices ranging from $0.7511 to $0.7779 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.

Key Figures

Shares sold: 5,172 shares Weighted average sales price: $0.7558 per share Shares sold: 2,493 shares +1 more

4 metrics

Shares sold 5,172 shares September 21, 2026

Weighted average sales price $0.7558 per share September 21, 2026

Shares sold 2,493 shares September 22, 2026

Weighted average sales price $0.7608 per share September 22, 2026

Key Terms

sell-to-cover provision, restricted stock units, weighted average sales price

3 terms

sell-to-cover provision financial

"mandatory sell-to-cover provision"

restricted stock units financial

"vesting of previously granted restricted stock units"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

weighted average sales price financial

"Represents the weighted average sales price per share"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

How many shares did QSI CFO Jeffry R. Keyes sell?

Jeffry R. Keyes reported sales of 5,172 shares on September 21, 2026, and 2,493 shares on September 22, 2026, totaling 7,665 shares.

What price ranges were reported for QSI CFO Jeffry R. Keyes's sales?

The September 21 sale had a weighted average price of $0.7558 per share, with shares sold at prices ranging from $0.75 to $0.762. The September 22 sale had a weighted average price of $0.7608 per share, with shares sold at prices ranging from $0.7511 to $0.7779.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 09/23/2026 - 07:46 PM Accepted by SEC EDGAR 09/23/2026 - 07:45 PM Learn about SEC filing dates

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

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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

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^*

Keyes Jeffry R.

(Last) (First) (Middle)

C/O QUANTUM-SI INCORPORATED

29 BUSINESS PARK DRIVE

(Street)

BRANFORD CONNECTICUT 06405

(City) (State) (Zip)

UNITED STATES

(Country)

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

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
09/21/2026

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

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

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

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	09/21/2026		S(1)		5,172	D	$0.7558(2)	1,719,177	D
Class A Common Stock	09/22/2026		S(1)		2,493	D	$0.7608(3)	1,716,684	D

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. Represents shares sold pursuant to a mandatory Quantum-Si sell-to-cover provision for required federal, state and local withholding taxes in connection with the vesting of previously granted restricted stock units. Individual is not able to alter this mandatory sell-to-cover provision that is enacted at the grant date of the related restricted stock unit award.

2. Represents the weighted average sales price per share. The shares sold at prices ranging from $0.75 to $0.762 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. Represents the weighted average sales price per share. The shares sold at prices ranging from $0.7511 to $0.7779 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.

	/s/ Christian LaPointe, Ph.D., Attorney-in-Fact.	09/23/2026
	** 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.
* Form 4: SEC 1474 (03-26)