Insider files to sell 17,922 Class A shares

Robert G. Spignesi filed a Form 144 notifying a proposed sale of 17,922 Class A shares arising from restricted stock vesting on 03/09/2026.

Accepted by SEC EDGAR 03/10/2026 - 04:26 PM EDT Learn about SEC filing dates

Rhea-AI Filing Summary

Robert G. Spignesi filed a Form 144 notifying a proposed sale of 17,922 Class A shares arising from restricted stock vesting on 03/09/2026.

The notice also reports prior sales of 12,840 Class A shares on 02/09/2026 for $48,569.87 and 38,327 Class A shares on 02/19/2026 for $148,911.89. Shares outstanding were reported as 39,823,026 as of 03/10/2026.

Insights

Equity Compliance Analyst

Routine affiliate resale notice for vested compensation shares.

The filing lists a proposed sale of 17,922 Class A shares tied to restricted stock vesting on 03/09/2026. This is a standard Form 144 disclosure notifying the market of an intended sale by an affiliate.

Prior reported transactions include 12,840 and 38,327 Class A share sales on 02/09/2026 and 02/19/2026. Cash‑flow treatment and whether sales are pursuant to a trading plan are not stated in the excerpt.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What did RPID insider Robert G. Spignesi report in the Form 144?

He reported a proposed sale of 17,922 Class A shares from restricted stock vesting on 03/09/2026, plus prior sales in February 2026.

How many shares did Spignesi sell earlier in 2026 according to the filing?

The filing shows sales of 12,840 Class A shares on 02/09/2026 and 38,327 Class A shares on 02/19/2026, with reported proceeds listed.

Does the Form 144 state the shares outstanding for RPID?

Yes; the excerpt reports 39,823,026 shares outstanding as of 03/10/2026, presented as a context figure in the filing.

Are the proceeds recipient and sale method disclosed in the excerpt?

The excerpt lists dollar amounts for prior sales but does not specify who receives proceeds or the distribution methods for the proposed sale.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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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	0001853904
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	RAPID MICRO BIOSYSTEMS, INC.
SEC File Number	001-40592
Address of Issuer	25 HARTWELL AVENUE LEXINGTON MASSACHUSETTS 02421
Phone	978-349-3200
Name of Person for Whose Account the Securities are To Be Sold	Spignesi Robert G. Jr.
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	Officer
Relationship to Issuer	Director

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	Fidelity Brokerage Services LLC 900 Salem Street Smithfield RI 02917	17922	73686.30	39823026	03/10/2026	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	03/09/2026	Restricted Stock Vesting	Issuer			17922	03/09/2026	Compensation

* 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
Robert G. Spignesi 25 Hartwell Avenue Lexington MA 02421	Class A	02/09/2026	12840	48569.87
Robert G. Spignesi 25 Hartwell Avenue Lexington MA 02421	Class A	02/19/2026	38327	148911.89

144: Remarks and Signature

Remarks	Sale includes an amount necessary to cover a tax obligation resulting from the settlement of a vested equity award distribution.
Date of Notice	03/10/2026
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	/s/ Jessica Spraker, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Robert G. Spignesi.
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)