RSU sale notice for Quantum-Si (NASDAQ: QSI) — 416,667 Class A shares

Rhea-AI Filing Summary

Quantum-Si Incorporated disclosed a Form 144 notice related to Class A Common Stock tied to a Restricted Stock Unit vesting event. The filing lists 416,667 shares associated with the RSU vesting dated 04/22/2026 and records a prior sale of 23,777 shares on 03/20/2026. The broker listed is Morgan Stanley Smith Barney LLC.

Insights

Securities Counsel

Form 144 notifies the market of a proposed Rule 144 sale following RSU vesting.

Form 144 is a regulatory notice used to declare an intention to sell restricted or control securities under Rule 144. This filing ties a planned sale to a Restricted Stock Unit vesting event of 416,667 shares dated 04/22/2026.

Timing and execution depend on Rule 144 conditions (holding period, current public information, manner-of-sale limits). The excerpt lists a prior sale of 23,777 shares on 03/20/2026; cash‑flow treatment or sale methods are not specified in the provided excerpt.

Key Figures

RSU vesting shares: 416,667 shares Prior sale: 23,777 shares Broker: Morgan Stanley Smith Barney LLC +1 more

4 metrics

RSU vesting shares 416,667 shares Restricted Stock Unit Vesting on 04/22/2026

Prior sale 23,777 shares Securities sold on 03/20/2026 (entry lists 19906.40 alongside)

Broker Morgan Stanley Smith Barney LLC Listed as filer/broker in the Form 144 entries

Planned sale date 04/22/2026 Date associated with RSU vesting and securities-to-be-sold

Key Terms

Restricted Stock Unit Vesting, Form 144, Class A Common Stock

3 terms

Restricted Stock Unit Vesting financial

"Restricted Stock Unit Vesting | Quantum-Si Incorporated"

Form 144 regulatory

"Filer Information | 144: Filer Information"

Form 144 is a document that investors must file with the government when they plan to sell a large number of shares of a company's stock. It helps ensure transparency so everyone knows how many shares are being sold and when, which can impact the stock's price.

Class A Common Stock financial

"Class A Common Stock | Morgan Stanley Smith Barney LLC"

Class A common stock is a category of a company’s shares that carries a specific set of ownership rights—most commonly defined voting power and claims on dividends—set out in the company’s charter. For investors it matters because the class determines how much influence you have over corporate decisions, the share’s likely dividend and trading behavior, and how it compares in value to other share classes, like choosing a particular seat with different privileges at the company’s decision-making table.

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

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	167424	167507.71	196431273	04/20/2026	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	04/22/2026	Restricted Stock Unit Vesting	Quantum-Si Incorporated			416667	04/22/2026	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	03/20/2026	23777	19906.40

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 Quantum-Si's Form 144 list for RSU-related shares?

Answer: The filing lists 416,667 shares tied to a Restricted Stock Unit vesting dated 04/22/2026. This figure is shown in the securities-to-be-sold section as equity compensation for services rendered.

Who is the broker handling the proposed sale in the QSI Form 144?

Answer: The broker named is Morgan Stanley Smith Barney LLC, with an address at 1 New York Plaza, 38th Floor, New York, NY. The broker appears in the filer and past-sales lines.

Does the Form 144 show recent sales prior to the RSU vesting?

Answer: Yes. The filing records a past sale of 23,777 shares on 03/20/2026. The excerpt includes a numeric value of 19906.40 alongside that sale entry.

Is the Form 144 an authorization to sell immediately?

Answer: Form 144 is a notice of intent to sell under Rule 144, not an automatic authorization. Execution depends on satisfying Rule 144 conditions and any sale mechanics; specific sale methods are not provided in the excerpt.

Which security class is involved in the filing for Quantum-Si?

Answer: The filing refers to Class A Common Stock on NASDAQ. The securities-to-be-sold entry links the Class A Common Stock to the RSU vesting dated 04/22/2026.