Quantum‑Si (NASDAQ: QSI) Form 144 names Morgan Stanley brokered sale

Rhea-AI Filing Summary

Quantum-Si Incorporated submitted a Form 144 notice concerning proposed dispositions of Class A Common Stock through Morgan Stanley Smith Barney LLC on 03/20/2026 for shares listed as 11959 and an amount shown as 10012.23 with exchange noted as NASDAQ.

The filing lists prior restricted stock unit vesting events of 18,063 shares on 03/15/2024 and 26,042 shares on 03/12/2025, and a sale during the past three months of 11,951 shares on 12/22/2025 with a figure shown as 15249.48.

Insights

Securities Counsel

Form 144 lists brokered proposed sales and recent vesting and a recent sale.

The notice names Morgan Stanley Smith Barney LLC as the broker and records a proposed sale entry dated 03/20/2026 with numeric entries 11959 and 10012.23 present in the excerpt. The exact interpretation of the numeric fields (shares, proceeds, or price) is as shown in the excerpt.

Timing and cash‑flow treatment beyond the dates and broker name are not detailed in the provided excerpt; subsequent SEC filings or broker confirmations would show completion details.

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK
Filer CCC
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer

SEC File Number

Address of Issuer

Phone

Name of Person for Whose Account the Securities are To Be Sold

See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.

Relationship to Issuer

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Class A Common Stock	Morgan Stanley Smith Barney LLC 1 New York Plaza 38th Floor New York NY 10004	11959	10012.23	196431273	03/20/2026	NASDAQ

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Class A Common Stock	03/15/2024	Restricted Stock Unit Vesting	Quantum-Si Incorporated			18063	03/15/2024	Equity compensation for services rendered
Class A Common Stock	03/12/2025	Restricted Stock Unit Vesting	Quantup-Si Incorporated			26042	03/12/2025	Equity compensation for services rendered

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
Morgan Stanley Smith Barney LLC 1 New York Plaza 38th Floor New York NY 10004	Class A Common Stock	12/22/2025	11951	15249.48

144: Remarks and Signature

Remarks

Date of Notice

ATTENTION:

The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.

Signature

ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)

FAQ

What does the QSI Form 144 disclose about the broker?

The Form 144 names Morgan Stanley Smith Barney LLC as the broker handling the transactions. The filing provides the broker's address and associates the proposed sale activity with that broker in the excerpt.

How many Class A shares are listed in the Form 144 excerpt for the proposed sale?

The excerpt shows a numeric entry of 11959 associated with Class A Common Stock for the proposed sale. The filing text presents this number alongside other numeric fields and dates.

Does the filing show recent vesting activity for QSI RSUs?

Yes. The excerpt lists RSU vesting of 18,063 shares on 03/15/2024 and 26,042 shares on 03/12/2025, labeled as equity compensation for services rendered.

Was any sale completed in the three months before the Form 144 date?

The excerpt records a sale on 12/22/2025 of 11,951 Class A shares with an associated figure 15249.48 shown in the same row of the filing.

Does the excerpt state the exchange on which the shares trade?

Yes. The filing excerpt identifies the exchange as NASDAQ in the securities information section tied to the Class A Common Stock entry.