Exhibit 4.1





 


FULLY-PAID
AND NON-ASSESSABLE SHARES OF CLASS A COMMON STOCK OF Rapid Micro Biosystems, Inc. (hereinafter called the “Company”),
transferable on the books of the Company in person or by duly authorized attorney, upon surrender of this Certificate properly endorsed.
This Certificate and the shares represented hereby, are issued and shall be held subject to all of the provisions of the Restated Certificate
of Incorporation, and the Amended and Restated Bylaws, of the Company (copies of which are on file with the Company and with the Transfer
Agent), to all of which each holder, by acceptance hereof, assents. This Certificate is not valid unless countersigned and registered
by the Transfer Agent and Registrar. Witness the facsimile seal of the Company and the facsimile signatures of its duly authorized
officers. CLASS A COMMON STOCK PAR VALUE $0.01 CLASS A COMMON STOCK SEE REVERSE FOR CERTAIN DEFINITIONS Certificate
Number Shares . RAPID MICRO BIOSYSTEMS, INC. INCORPORATED UNDER THE LAWS OF THE STATE OF DELAWARE FACSIMILE SIGNATURE TO COME
FACSIMILE SIGNATURE TO COME President Secretary By AUTHORIZED SIGNATURE 12/29/2006 DEL AWAR E CO R PO RATE RAPID MICRO BIOSYSTEMS,
INC. ZQ|CERT#|COY|CLS|RGSTRY|ACCT#|TRANSTYPE|RUN#|TRANS# XXXXXX XX X DD-MMM-YYYY * * 000000* * * * * * * * * * * * * * * * * * * * *
000000* * * * * * * * * * * * * * * * * * * * * 000000* * * * * * * * * * * * * * * * * * * * * 000000* * * * * * * * * * * * * * * *
* * * * * 000000* * * * * * * * * * * * * * ** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample
**** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample ****
Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander
David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David
Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample
**** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample ****
Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander
David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David
Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample
**** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample ****
Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander
David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David
Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Sample **** Mr. Sample **000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares***
*000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****
000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****0
00000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****00
0000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000
000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****0000
00**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****00000
0**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000
**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000*
*Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**
Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**S
***ZERO HUNDRED THOUSAND ZERO HUNDRED AND ZERO*** MR. SAMPLE & MRS. SAMPLE & MR. SAMPLE & MRS. SAMPLE ZQ00000000 Certificate
Numbers 1234567890/1234567890 1234567890/1234567890 1234567890/1234567890 1234567890/1234567890 1234567890/1234567890 1234567890/1234567890
Total Transaction Num/No. 123456 Denom. 123456 Total 1234567 MR A SAMPLE DESIGNATION (IF ANY) ADD 1 ADD 2
ADD 3 ADD 4 PO BOX 505006, Louisville, KY 40233-5006 CUSIP/IDENTIFIER XXXXXX XX X Holder ID XXXXXXXXXX Insurance Value
1,000,000.00 Number of Shares 123456 DTC 12345678 123456789012345 THIS CERTIFICATE IS TRANSFERABLE IN CITIES DESIGNATED
BY THE TRANSFER AGENT, AVAILABLE ONLINE AT www.computershare.com Exhibit 4.1 DATED COUNTERSIGNED AND REGISTERED: COMPUTERSHARE
TRUST COMPANY, N.A. TRANSFER AGENT AND REGISTRAR,


 



    


     


    

 





 


For value
received, ____________________________hereby sell, assign and transfer unto ________________________________________________________________________________________________________________________________
________________________________________________________________________________________________________________________________ ________________________________________________________________________________________________________________________________
_______________________________________________________________________________________________________________________ Shares _______________________________________________________________________________________________________________________
Attorney Dated: __________________________________________20__________________ Signature: ____________________________________________________________
Signature: ____________________________________________________________ Notice: The signature to this assignment must correspond with
the name as written upon the face of the certificate, in every particular, without alteration or enlargement, or any change whatever.
PLEASE INSERT SOCIAL SECURITY OR OTHER IDENTIFYING NUMBER OF ASSIGNEE (PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING POSTAL ZIP
CODE, OF ASSIGNEE) of the Class A Common Stock represented by the within Certificate, and do hereby irrevocably constitute and appoint
to transfer the said stock on the books of the within-named Company with full power of substitution in the premises. . RAPID MICRO BIOSYSTEMS,
INC. THE COMPANY WILL FURNISH WITHOUT CHARGE TO EACH SHAREHOLDER WHO SO REQUESTS, A SUMMARY OF THE POWERS, DESIGNATIONS, PREFERENCES
AND RELATIVE, PARTICIPATING, OPTIONAL OR OTHER SPECIAL RIGHTS OF EACH CLASS OF STOCK OF THE COMPANY AND THE QUALIFICATIONS, LIMITATIONS
OR RESTRICTIONS OF SUCH PREFERENCES AND RIGHTS, AND THE VARIATIONS IN RIGHTS, PREFERENCES AND LIMITATIONS DETERMINED FOR EACH SERIES,
WHICH ARE FIXED BY THE ARTICLES OF INCORPORATION OF THE COMPANY, AS AMENDED, AND THE RESOLUTIONS OF THE BOARD OF DIRECTORS OF THE COMPANY,
AND THE AUTHORITY OF THE BOARD OF DIRECTORS TO DETERMINE VARIATIONS FOR FUTURE SERIES. SUCH REQUEST MAY BE MADE TO THE OFFICE OF THE
SECRETARY OF THE COMPANY OR TO THE TRANSFER AGENT. THE BOARD OF DIRECTORS MAY REQUIRE THE OWNER OF A LOST OR DESTROYED STOCK CERTIFICATE,
OR HIS LEGAL REPRESENTATIVES, TO GIVE THE COMPANY A BOND TO INDEMNIFY IT AND ITS TRANSFER AGENTS AND REGISTRARS AGAINST ANY CLAIM THAT
MAY BE MADE AGAINST THEM ON ACCOUNT OF THE ALLEGED LOSS OR DESTRUCTION OF ANY SUCH CERTIFICATE. Signature(s) Guaranteed: Medallion Guarantee
Stamp THE SIGNATURE(S) SHOULD BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION (Banks, Stockbrokers, Savings and Loan Associations
and Credit Unions) WITH MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM, PURSUANT TO S.E.C. RULE 17Ad-15. The following
abbreviations, when used in the inscription on the face of this certificate, shall be construed as though they were written out in full
according to applicable laws or regulations: TEN COM - as tenants in common UNIF GIFT MIN ACT - ............................................Custodian
................................................. (Cust) (Minor) TEN ENT - as tenants by the entireties under Uniform Gifts to Minors
Act ........................................................ (State) JT TEN - as joint tenants with right of survivorship UNIF TRF MIN
ACT - ............................................Custodian (until age ................................) and not as tenants in common
(Cust) .............................under Uniform Transfers to Minors Act ................... (Minor) (State) Additional abbreviations
may also be used though not in the above list.