Quantum-Si CFO sells shares for tax withholding

Quantum-Si Inc Chief Financial Officer Jeffry R. Keyes reported mandatory tax-related share sales.

Rhea-AI Filing Summary

Quantum-Si Inc Chief Financial Officer Jeffry R. Keyes reported mandatory tax-related share sales. He sold 37,382 shares of Class A Common Stock on April 20, 2026 at a weighted average price of $1.0064 per share and 37,381 shares on April 21, 2026 at a weighted average price of $0.9950 per share.

According to the footnotes, both transactions were executed under a mandatory Quantum-Si sell-to-cover provision to satisfy federal, state and local withholding taxes associated with vesting restricted stock units, and he could not alter this provision. After these transactions, he directly owns 1,732,582 Class A shares.

Insider Trade Summary

Net Seller: 74,763 shares

Net Sell 2 txns

Insider Keyes Jeffry R.

Role Chief Financial Officer

Sold 74,763 shs ($75K)

Type	Security	Shares	Price	Value
Sale	Class A Common Stock	37,381	$0.995	$37K
Sale	Class A Common Stock	37,382	$1.0064	$38K

Holdings After Transaction: Class A Common Stock — 1,732,582 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 $0.9811 to $1.05 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 $0.9763 to $1.04 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 2026-04-20: 37,382 shares at $1.0064 Shares sold 2026-04-21: 37,381 shares at $0.9950 Total shares sold: 74,763 shares +3 more

6 metrics

Shares sold 2026-04-20 37,382 shares at $1.0064 Class A Common Stock, weighted average sale price on April 20, 2026

Shares sold 2026-04-21 37,381 shares at $0.9950 Class A Common Stock, weighted average sale price on April 21, 2026

Total shares sold 74,763 shares Aggregate Class A shares sold across both tax-related transactions

Post-transaction holdings 1,732,582 shares CFO’s direct Class A Common Stock ownership after April 21, 2026

Price range 2026-04-20 $0.9763–$1.04 per share Footnote F3 trade price range for April 20, 2026 sales

Price range 2026-04-21 $0.9811–$1.05 per share Footnote F2 trade price range for April 21, 2026 sales

Key Terms

sell-to-cover provision, restricted stock units, weighted average sales price per share, open-market sale

4 terms

sell-to-cover provision financial

"Represents shares sold pursuant to a mandatory Quantum-Si sell-to-cover provision for required federal, state and local withholding taxes"

restricted stock units financial

"withholding taxes in connection with the 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 per share financial

"Represents the weighted average sales price per share. The shares sold at prices ranging from"

open-market sale financial

"transaction_action": "open-market sale""

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

FAQ

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

What insider transaction did Quantum-Si (QSI) disclose for its CFO?

Quantum-Si disclosed that CFO Jeffry R. Keyes sold 74,763 Class A shares over two days. These sales were linked to tax withholding on vesting restricted stock units rather than discretionary selling in the open market, according to the filing footnotes.

Why did Quantum-Si (QSI) CFO Jeffry Keyes sell 74,763 shares?

The shares were sold under a mandatory sell-to-cover provision for tax withholding on vested restricted stock units. The filing states this provision covers federal, state and local taxes and was set at the RSU grant date, so the CFO could not change these sales.

At what prices did the Quantum-Si (QSI) CFO’s shares sell?

On April 20, 2026, 37,382 shares sold at a weighted average price of $1.0064. On April 21, 2026, 37,381 shares sold at a weighted average price of $0.9950. Footnotes note underlying trade prices ranged roughly between $0.98 and $1.05 per share.

How many Quantum-Si (QSI) shares does the CFO hold after these transactions?

After completing the tax-related sales, CFO Jeffry R. Keyes directly owns 1,732,582 shares of Quantum-Si Class A Common Stock. This post-transaction holding figure comes directly from the Form 4 and reflects his remaining equity stake following the sell-to-cover activity.

Were the Quantum-Si (QSI) CFO’s share sales discretionary open-market trades?

Although coded as open-market sales, the footnotes describe them as mandatory sell-to-cover transactions. They were executed to satisfy required tax withholding on vesting restricted stock units, and the CFO could not alter this pre-set sell-to-cover mechanism.

What does a mandatory sell-to-cover provision mean for Quantum-Si (QSI) insiders?

A mandatory sell-to-cover provision automatically sells enough shares when restricted stock units vest to cover tax withholding obligations. For Quantum-Si, the filing explains this mechanism applied to the CFO’s RSU vesting, turning it into a tax event rather than a discretionary portfolio decision.

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

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Accepted by SEC EDGAR 04/22/2026 - 05:09 PM EDT 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)
04/20/2026

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	04/20/2026		S(1)		37,382	D	$1.0064(2)	1,769,963	D
Class A Common Stock	04/21/2026		S(1)		37,381	D	$0.995(3)	1,732,582	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 $0.9811 to $1.05 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 $0.9763 to $1.04 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.	04/22/2026
	** 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)