Rapid Micro Biosystems files Form 144 for 11.8k Class A share sale

Rhea-AI Filing Summary

Rapid Micro Biosystems, Inc. (symbol: RPID) has filed a Form 144 disclosing an insider’s intent to sell shares. Robert G. Spignesi plans to dispose of 11,874 Class A shares on or about 11 July 2025 via NASDAQ, using Fidelity Brokerage Services as broker. At the reference price in the notice, the sale is valued at roughly $39,498.86. The filing cites the shares as recently vested restricted stock received as compensation on 10 July 2025.

The document also lists three prior transactions by the same insider between 8-10 July 2025 totaling 33,688 shares for gross proceeds of $116,981.01. With 39,332,172 shares outstanding, the forthcoming sale represents about 0.03 % of the company’s float, indicating a routine liquidity event rather than a material ownership change.

Insights

Securities Analyst

TL;DR: Minor insider sale (11,874 shares) equals 0.03% of float—immaterial impact on valuation or control.

Form 144 filings alert investors to prospective insider sales. Here, Robert G. Spignesi intends to sell 11,874 Class A shares worth roughly $39.5k, following three similar-sized transactions earlier in the week. Given Rapid Micro Biosystems’ 39.3 million shares outstanding, the proposed disposal is negligible. The shares stem from routine restricted-stock vesting, not open-market purchases, suggesting normal portfolio diversification rather than a strategic signal. No adverse information is asserted by the filer, and the notice does not alter the investment thesis in a meaningful way.

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	11874	39498.86	39332172	07/11/2025	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	07/10/2025	Restricted Stock Vesting	Issuer			11874	07/10/2025	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

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 sold under this Form 144?

11,874 Class A shares are slated for sale.

What is the estimated market value of the planned RPID share sale?

The notice lists an aggregate value of $39,498.86.

When is the anticipated sale date for the insider transaction?

The approximate date of sale is 11 July 2025.

What percentage of Rapid Micro Biosystems’ outstanding shares does this sale represent?

With 39,332,172 shares outstanding, the sale equals about 0.03 % of total shares.

Have there been recent sales by the same insider?

Yes. Between 8-10 July 2025, the insider sold 33,688 shares for gross proceeds of $116,981.01.

What class of securities is being sold?

The filing covers Class A common shares of Rapid Micro Biosystems.