Were John Vieceli’s Quantum-Si (QSI) share sales discretionary trades?

The sales were made under a mandatory Quantum-Si sell-to-cover provision. According to the footnotes, this provision covers required tax withholding upon RSU vesting and is enacted at the award’s grant date, which the individual is not able to alter.

Quantum-Si (QSI) CPO sells 30,223 shares to cover RSU tax withholding

Filing Impact

(Neutral)

Filing Sentiment

(Negative)

Form Type

Rhea-AI Filing Summary

Quantum-Si Inc Chief Product Officer John S. Vieceli reported sales of 30,223 shares of Class A Common Stock to cover tax obligations tied to vesting restricted stock units. The transactions occurred on June 22 and June 23 in open-market sales under a mandatory sell-to-cover provision that was set at the grant date and cannot be altered by the individual.

Shares were sold at weighted average prices of $0.9574 and $0.899 per share across price ranges described in the footnotes. After these sales, Vieceli directly holds 1,140,434 shares of Quantum-Si Class A Common Stock, indicating he retains a substantial equity position.

Insider Trade Summary

Net Seller: 30,223 shares ($28,053)

Net Sell 2 txns

Insider Vieceli John S.

Role Chief Product Officer

Sold 30,223 shs ($28K)

Type	Security	Shares	Price	Value
Sale	Class A Common Stock	15,112	$0.899	$14K
Sale	Class A Common Stock	15,111	$0.9574	$14K

Holdings After Transaction: Class A Common Stock — 1,140,434 shares (Direct, null)

Footnotes (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. Represents the weighted average sales price per share. The shares sold at prices ranging from $0.9212 to $1.005 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. Represents the weighted average sales price per share. The shares sold at prices ranging from $0.88 to $0.9291 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 June 22: 15,111 shares Price June 22: $0.9574/share Shares sold June 23: 15,112 shares +5 more

8 metrics

Shares sold June 22 15,111 shares Class A Common Stock sold on June 22, 2026

Price June 22 $0.9574/share Weighted average sales price June 22, 2026

Shares sold June 23 15,112 shares Class A Common Stock sold on June 23, 2026

Price June 23 $0.899/share Weighted average sales price June 23, 2026

Total shares sold 30,223 shares Net shares sold across both reported transactions

Shares held after 1,140,434 shares Direct Class A holdings following the June 23, 2026 sale

Price range June 22 $0.9212–$1.005/share Range of individual trade prices June 22, 2026

Price range June 23 $0.88–$0.9291/share Range of individual trade prices June 23, 2026

Key Terms

sell-to-cover provision, restricted stock units, weighted average sales price, open-market sale, +1 more

5 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 financial

"Represents the weighted average sales price per share. The shares sold at prices ranging from $0.9212 to $1.005 per share"

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.

withholding taxes financial

"for required federal, state and local withholding taxes in connection with the vesting"

Withholding taxes are amounts a payer or government takes out of payments — such as wages, interest, or dividends — before the recipient gets the money, functioning like a cashier keeping part of a bill to pay taxes on your behalf. For investors this matters because it reduces the cash they actually receive, affects net returns and yield calculations, and may require additional paperwork or treaty claims to recover or offset the withheld amount against final tax bills.

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Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 06/24/2026 - 08:17 PM Accepted by SEC EDGAR 06/24/2026 - 08:17 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

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^*

Vieceli John S.

(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 Product Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
06/22/2026

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Class A Common Stock	06/22/2026		S⁽¹⁾		15,111	D	$0.9574⁽²⁾	1,155,546	D
Class A Common Stock	06/23/2026		S⁽¹⁾		15,112	D	$0.899⁽³⁾	1,140,434	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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)

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 $0.9212 to $1.005 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 $0.88 to $0.9291 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.	06/24/2026
	** 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)

Source: View Original Filing on SEC EDGAR

FAQ

What did Quantum-Si (QSI) Chief Product Officer John Vieceli report in this Form 4?

John S. Vieceli reported selling 30,223 Quantum-Si Class A shares. These sales were made to cover required federal, state and local withholding taxes triggered by the vesting of previously granted restricted stock units, under a mandatory sell-to-cover provision set at grant.

At what prices were the Quantum-Si (QSI) shares sold in Vieceli’s Form 4?

Vieceli’s shares were sold at weighted average prices of $0.9574 and $0.899 per share. The June 22 sales ranged from $0.9212 to $1.005 per share, and the June 23 sales ranged from $0.88 to $0.9291 per share, as detailed in the footnotes.

How many Quantum-Si (QSI) shares does John Vieceli hold after these transactions?

After the reported sales, Vieceli directly holds 1,140,434 Quantum-Si Class A shares. This reflects his remaining equity position following the 30,223 shares sold to satisfy tax withholding obligations related to vesting restricted stock units.

What is a sell-to-cover provision as used in this Quantum-Si (QSI) filing?

A sell-to-cover provision automatically sells shares to cover tax withholding when awards vest. In this case, Quantum-Si’s provision required selling a portion of vested restricted stock units to pay federal, state and local taxes due at vesting.

How many Quantum-Si (QSI) shares did John Vieceli sell on each transaction date?

Vieceli sold 15,111 shares on June 22 and 15,112 shares on June 23. Both transactions involved Class A Common Stock, executed as open-market sales, and were tied to a mandatory sell-to-cover tax provision following RSU vesting.