Quantum-Si Insider Vieceli Files Form 4 on Ownership Change

TL;DR

**Quantum-Si insider Vieceli filed a Form 4, signaling a change in his ownership.**

AI Summary

John S. Vieceli, an insider at Quantum-Si Inc., filed a Form 4 on March 24, 2026, indicating a change in his beneficial ownership of the company's securities as of March 20, 2026. This filing, while not detailing specific transactions, signals that an executive's stake in the company has shifted. For investors, understanding these changes is crucial because insider activity can sometimes hint at management's confidence (or lack thereof) in the company's future prospects, potentially influencing stock performance.

Why It Matters

Insider transaction filings like this Form 4 provide transparency into how executives are managing their personal holdings in the company, which can be a signal to the market.

Risk Assessment

Risk Level: low — This filing is purely informational, indicating a change in beneficial ownership without specifying the transaction details, thus posing minimal direct risk.

Analyst Insight

Investors should monitor subsequent filings or news from Quantum-Si Inc. to understand the specific nature of John S. Vieceli's ownership change, as this filing only indicates a change occurred without detailing the transaction (e.g., buy, sell, grant).

Key Players & Entities

• Vieceli John S. (person) — Reporting person, an insider at Quantum-Si Inc.
• Quantum-Si Inc (company) — The issuer of the securities
• 0001816431 (company) — CIK for Quantum-Si Inc.
• 0002032947 (person) — CIK for Vieceli John S.

FAQ

Key Financial Figures

• $0.8314 — The shares sold at prices ranging from $0.8314 to $0.8718 per share. Full information
• $0.8718 — sold at prices ranging from $0.8314 to $0.8718 per share. Full information regarding t
• $0.7973 — The shares sold at prices ranging from $0.7973 to $0.8525 per share. Full information
• $0.8525 — sold at prices ranging from $0.7973 to $0.8525 per share. Full information regarding t

Filing Documents

• form4.html (4)
• form4.xml (4) — 6KB
• 0001140361-26-010945.txt ( ) — 7KB

From the Filing

SEC FORM 4 SEC Form 4 FORM 4 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 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) 03/20/2026 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 03/20/2026 S (1) 10,758 D $ 0.8483 (2) 1,181,896 D Class A Common Stock 03/23/2026 S (1) 11,239 D $ 0.8266 (3) 1,170,657 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 $0.8314 to $0.8718 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 $0.7973 to $0.8525 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. 03/24/2026 ** 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)

View Full Filing

View this 4 filing on SEC EDGAR