RAPID MICRO BIOSYSTEMS INC

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of

the Securities Exchange Act of 1934 (Amendment No. )

Rapid Micro Biosystems, Inc.

(Name of Registrant as Specified in its Charter)

(Name of Person(s) Filing Proxy Statement, if Other Than the Registrant)

NOTICE & PROXY

STATEMENT

2025 Annual Meeting of Stockholders

To be Held on

Thursday, May 22, 2025

9:00 a.m. Eastern Time

25 HARTWELL AVENUE

LEXINGTON, MASSACHUSETTS 02421

Dear Fellow Stockholders:

You are cordially invited to attend the 2025 Annual Meeting of Stockholders (“Annual Meeting”) of Rapid Micro Biosystems, Inc. (the “Company”), which will be conducted virtually via live webcast on Thursday, May 22, 2025, beginning at 9:00 a.m. Eastern Time. You will be able to attend the virtual Annual Meeting, vote your shares electronically and submit your questions during the Annual Meeting by visiting www.virtualshareholdermeeting.com/RPID2025. We believe that the virtual meeting format will allow stockholders to participate from any location and will lead to increased attendance, improved communications, lowered environmental impacts from travel and cost savings for our stockholders and the Company.

The notice of the Annual Meeting and proxy statement on the following pages describe the matters to be presented at the Annual Meeting. Details regarding how to attend the Annual Meeting and the business to be conducted at the Annual Meeting are more fully described in the accompanying notice of the Annual Meeting and proxy statement.

Whether or not you attend the Annual Meeting, it is important that your shares be represented and voted in advance of or at the Annual Meeting. We are providing proxy material access to our stockholders online at www.proxyvote.com. Online distribution of our proxy materials conserves natural resources, lowers the cost of the Annual Meeting, and expedites receipt by stockholders. The matters to be acted upon at the Annual Meeting are also described in the Notice of Internet Availability of Proxy Materials ("Notice of Internet Availability") that you will receive in the mail. Please give the proxy materials your careful attention.

You may vote online or by telephone by following the instructions on your Notice of Internet Availability. In order to vote online or by telephone, you must have the stockholder identification number provided in your Notice of Internet Availability. If you requested a proxy card by mail, you may vote by completing, signing and returning the proxy card in the postage-paid envelope provided. If you attend the Annual Meeting online, you may vote electronically at the Annual Meeting even if you previously returned your proxy card by mail or voted online or by telephone. Please review the instructions for each voting option described in the Notice of Internet Availability and in the accompanying proxy statement.

Your vote is very important to us and to our business. Prior to the Annual Meeting, we encourage all of our stockholders to review these proxy materials and vote their shares.

Thank you for your support.

Sincerely,

Robert Spignesi

President and Chief Executive Officer

Kirk D. Malloy, Ph.D.

Chair of the Board of Directors

Notice of 2025 Annual Meeting of Stockholders

To be Held on Thursday, May 22, 2025

25 HARTWELL AVENUE

LEXINGTON, MASSACHUSETTS 02421

The 2025 Annual Meeting of Stockholders (“Annual Meeting”) of Rapid Micro Biosystems, Inc., a Delaware corporation (the “Company”), will be held at 9:00 a.m., Eastern Time, on Thursday, May 22, 2025. The Annual Meeting will be conducted virtually via live webcast. You will be able to attend the Annual Meeting, vote your shares electronically and submit your questions during the Annual Meeting by visiting www.virtualshareholdermeeting.com/RPID2025. The Annual Meeting is called for the following purposes:

(1)To elect Inese Lowenstein and Dafni Bika as Class I Directors to serve until the 2028 Annual Meeting of Stockholders and until their respective successors have been duly elected and qualified, or until their earlier death, resignation or removal;

(2)To ratify the appointment of PricewaterhouseCoopers LLP as our independent registered public accounting firm for the fiscal year ending December 31, 2025; and

(3)To transact such other business as may properly come before the Annual Meeting or any continuation, postponement, or adjournment of the Annual Meeting.

Only holders of record of our outstanding shares of Class A common stock at the close of business on April 7, 2025, are entitled to notice of and to vote at the Annual Meeting, or any continuation, postponement or adjournment of the Annual Meeting. A list of stockholders entitled to vote at the Annual Meeting will be available at 25 Hartwell Avenue, Lexington, Massachusetts 02421 for 10 days before the Annual Meeting and, during the Annual Meeting, such list will be available to registered stockholders as a link on the online Annual Meeting platform. The Annual Meeting may be continued, postponed or adjourned from time to time without notice other than by announcement at the Annual Meeting. The holders of our Class B common stock are not entitled to notice of, or to vote on, any matter before the Annual Meeting.

IMPORTANT NOTICE REGARDING THE INTERNET AVAILABILITY OF PROXY MATERIALS FOR THE ANNUAL MEETING TO BE HELD ON MAY 22, 2025:

We are providing proxy material access to our stockholders via the Internet at www.proxyvote.com. The matters to be acted upon at the Annual Meeting are described in the Notice of Internet Availability that you receive in the mail. Please give the proxy materials your careful attention.

In addition to their availability at www.proxyvote.com, this proxy statement and our 2024 Annual Report to stockholders are available for viewing, printing and downloading at investors.rapidmicrobio.com.

It is important that your shares be represented regardless of the number of shares you may hold. Whether or not you plan to attend the Annual Meeting, we urge you to vote your shares via the toll-free telephone number or online, as described in the enclosed materials. If you received a copy of the proxy card by mail, you may complete, sign, date and mail the proxy card in the enclosed return envelope. Promptly voting your shares will ensure the presence of a quorum at the Annual Meeting and will save us the expense of further solicitation. Submitting your proxy now will not prevent you from voting your shares at the Annual Meeting if you desire to do so, as your proxy is revocable at your option.

By Order of the Board of Directors

James Xu

SVP, Legal and Secretary

Lexington, Massachusetts

Your vote is important. Please vote.