Director buys 500,000 Quantum-Si (QSI) shares in open-market trade

Rhea-AI Filing Summary

Quantum-Si Inc director Charles R. Kummeth reported an open-market purchase of 500,000 shares of Class A common stock on March 5, 2026. The weighted average purchase price was $0.9196 per share, with individual trades executed between $0.8906 and $0.9735 per share. Following this transaction, he directly holds 855,000 shares of Quantum-Si common stock.

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Equity ownership & insider trading analyst

Quantum-Si director added 500,000 shares in an open-market buy.

Director Charles R. Kummeth executed an open-market purchase of 500,000 Quantum-Si Class A common shares at a weighted average price of $0.9196 per share on March 5, 2026. The filing notes trade prices ranged from $0.8906 to $0.9735 per share.

After the transaction, his direct holdings increased to 855,000 shares. Because this is an open-market purchase rather than an option exercise or automatic transaction, it reflects a discretionary decision to increase exposure, though the filing does not state his reasons or any broader implications.

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).

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^*

Kummeth Charles R.

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

3. Date of Earliest Transaction (Month/Day/Year)
03/05/2026

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	03/05/2026		P		500,000	A	$0.9196(1)	855,000	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 the weighted average purchase price per share. The shares were purchased at prices ranging from $0.8906 to $0.9735 per share. Full information regarding the number of shares purchased 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.	03/09/2026
	** 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.

FAQ

What did Quantum-Si (QSI) director Charles R. Kummeth report in this Form 4?

He reported buying 500,000 shares of Quantum-Si Class A common stock in an open-market transaction. The weighted average price was $0.9196 per share, with trades between $0.8906 and $0.9735, increasing his direct holdings to 855,000 shares.

How many Quantum-Si (QSI) shares does Charles R. Kummeth own after the reported trade?

After the reported transaction, Charles R. Kummeth directly owns 855,000 shares of Quantum-Si Class A common stock. This reflects an increase from his prior position following the purchase of 500,000 shares on March 5, 2026, at a weighted average price of $0.9196.

At what prices did Quantum-Si (QSI) director Charles R. Kummeth purchase his shares?

The weighted average purchase price was $0.9196 per share. According to the footnote, individual trades were executed in a range from $0.8906 to $0.9735 per share, with full price-breakdown details available upon request to the company, regulators, or shareholders.

Was the Quantum-Si (QSI) insider transaction an open-market purchase or another type of trade?

The transaction was an open-market purchase of Quantum-Si Class A common stock. The Form 4 identifies the code as “P,” described as a purchase in an open-market or private transaction, and classifies the holding as directly owned by Charles R. Kummeth.

What type of security did Quantum-Si (QSI) director Charles R. Kummeth acquire in this filing?

He acquired Quantum-Si Class A Common Stock. The Form 4 lists one non-derivative transaction in this security type, totaling 500,000 shares purchased, and shows that his total directly owned Class A share position is now 855,000 shares after the trade.