Company: RPID
Filing Date: 2025-02-28
Form Type: S-8
Source: 0001380106-25-000061
Chunk: 1

Company: RAPID MICRO BIOSYSTEMS, INC.
Filing Date: 2025-02-28
Form: S-8
Chunk 1
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 company |     | x |
|                         |     |   |     | Emerging growth company   |     | x |

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ¨

### EXPLANATORY NOTE
This Registration Statement on Form S-8 (this “Registration Statement”) is being filed by Rapid Micro Biosystems, Inc. (the “Registrant”) for the purpose of registering (i) 1,886,462 additional shares of Class A common stock, par value $0.01 per share (“Common Stock”), under the Registrant’s 2021 Incentive Award Plan (the “2021 Plan”), which were added on January 1, 2025 as a result of an automatic annual increase provision therein and (ii) 377,292 additional shares of Common Stock under the Registrant’s 2021 Employee Stock Purchase Plan (the “ESPP”), which were added on January 1, 2025 as a result of an automatic annual increase provision therein.

This Registration Statement also registers 476,000 additional shares of Common Stock under the Registrant’s 2023 Inducement Plan, as amended by the Second Amendment to the Inducement Plan (as amended, the “Inducement Plan”), pursuant to which the aggregate number of shares of Common Stock reserved and available for issuance under the Inducement Plan was increased by 476,000 shares.

All of the additional shares of Common Stock registered on this Registration Statement are of the same class as other securities for which a registration statement is effective. This Registration Statement is being filed for the purpose of increasing the number of shares of Common Stock issuable pursuant to the 2021 Plan, ESPP and Inducement Plan, and re-registering shares of Common Stock underlying forfeited restricted stock units previously granted under the 2021 Plan and the Inducement Plan. The Registrant’s registration statements on Form S-8 filed on July 16, 2021 (File No. 333-257981) , relating to the 2021 Plan and the ESPP, and on May 4, 2023 (File No. 333-271659) , relating to the Inducement Plan, are hereby incorporated by reference pursuant to General Instruction E.

# PART I
<div align='center'>INFORMATION REQUIRED IN