[144] Rapid Micro Biosystems, Inc. SEC Filing

Rhea-AI Filing Summary

Rapid Micro Biosystems, Inc. (RPID) filed a LIVE Form 144 indicating that shareholder Robert G. Spignesi intends to sell up to 11,881 Class A shares through Fidelity Brokerage Services on or about 14 July 2025. At the disclosed aggregate market value of $39,480.56, the transaction equates to roughly 0.03 % of the company’s 39,332,172 shares outstanding, signalling minimal dilution.

The shares were acquired on 11 July 2025 via restricted-stock vesting and are therefore compensation related. The filing also details four prior sales by the same holder between 8-11 July 2025 totalling 45,562 shares for gross proceeds of about $156,780. Under Rule 144, the filer certifies that no non-public material adverse information is known.

• Class of security: Class A common
• Broker: Fidelity Brokerage Services LLC, Smithfield, RI
• Proposed exchange: NASDAQ
• Recent selling cadence: ~11–12 k shares per day during 8-11 July 2025

While the absolute dollar amount is modest, the consecutive insider sales may be monitored by investors as a sentiment indicator.

Positive

• Transparent disclosure via timely Form 144 allows investors to track insider activity.
• Dilution impact is negligible: 11,881 shares equal ~0.03 % of total shares outstanding.

Negative

• Continued insider selling (over 57 k shares within one week) may be interpreted as weak insider conviction.
• Additional market supply of shares could exert minor short-term pressure on RPID’s share price.

Insights

Financial Analyst

TL;DR: Small, routine insider sale; negligible dilution, modest negative sentiment.

The Form 144 registers another 11,881 RPID shares for sale by Robert G. Spignesi, following four sales over the preceding week. Collectively (~57 k shares) the disposals represent only 0.15 % of outstanding shares and stem from RSU vesting, suggesting liquidity management rather than a strategic exit. The dollar value is immaterial and should not affect fundamentals, but continuing insider supply can weigh marginally on market perception until absorbed.

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	Fidelity Brokerage Services LLC 900 Salem Street Smithfield RI 02917	11881	39480.56	39332172	07/14/2025	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	07/11/2025	Restricted Stock Vesting	Issuer			11881	07/11/2025	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	07/08/2025	10824	38021.46
Robert G. Spignesi 25 Hartwell Avenue Lexington MA 02421	Class A	07/09/2025	11247	39480.34
Robert G. Spignesi 25 Hartwell Avenue Lexington MA 02421	Class A	07/10/2025	11617	39479.21
Robert G. Spignesi 25 Hartwell Avenue Lexington MA 02421	Class A	07/11/2025	11874	39498.86

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

How many Rapid Micro Biosystems (RPID) shares are being registered for sale?

The filing covers 11,881 Class A shares under Rule 144.

What is the approximate market value of the shares to be sold?

The aggregate value stated is $39,480.56.

When is the proposed sale date for the RPID shares?

The filer lists an approximate sale date of 14 July 2025.

How many shares of Rapid Micro Biosystems are outstanding according to the filing?

The document shows 39,332,172 shares outstanding.

What insider sales occurred during the past three months?

Between 8-11 July 2025, Robert G. Spignesi sold 45,562 shares for gross proceeds of roughly $156,780.

How were the shares being sold originally acquired?

They were acquired through restricted-stock vesting on 11 July 2025 as compensation.