[Form 4] RAPID MICRO BIOSYSTEMS, INC. Insider Trading Activity

Rhea-AI Filing Summary

Rapid Micro Biosystems, Inc. reported an equity compensation grant to its Chief Financial Officer, Sean M. Wirtjes. On February 11, 2026, he received 97,000 Class A common stock restricted stock units, awarded at $0 per share, increasing his directly held Class A shares to 580,928 after the grant.

He was also granted a stock option for 193,000 shares of Class A common stock with an exercise price of $4.2 per share. The RSUs vest in three annual installments starting on the first anniversary of the grant date, while the option vests in 48 equal monthly installments beginning March 11, 2026, contingent on continued service.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

WIRTJES SEAN M

(Last) (First) (Middle)

C/O RAPID MICRO BIOSYSTEMS, INC.

25 HARTWELL AVENUE

(Street)

LEXINGTON MA 02421

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
RAPID MICRO BIOSYSTEMS, INC. [ RPID ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	CHIEF FINANCIAL OFFICER

3. Date of Earliest Transaction (Month/Day/Year)
02/11/2026

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Class A Common Stock	02/11/2026		A		97,000(1)	A	$0	580,928	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (Right to Buy)	$4.2	02/11/2026		A		193,000		(2)	02/10/2036	Class A Common Stock	193,000	$0	193,000	D

Explanation of Responses:

1. Grant of restricted stock units ("RSUs") that vest in three annual installments with 33.4% vesting on the first anniversary of February 11, 2026 (the "grant date") and 33.3% vesting on each of the second and third anniversaries of the grant date provided that the Reporting Person remains in continuous service on each vesting date.

2. The option vests and becomes exercisable in 48 substantially equal monthly installments with the first installment vesting on March 11, 2026.

Remarks:

	/s/ Sean M. Wirtjes	02/13/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What equity awards did RPID grant to its CFO Sean M. Wirtjes?

Sean M. Wirtjes received 97,000 RSUs and 193,000 stock options. The RSUs are Class A common stock units, and the options allow him to buy Class A shares at $4.2 per share under the company’s compensation program.

How do the 97,000 RSUs granted to RPID’s CFO vest over time?

The 97,000 RSUs vest in three annual installments. 33.4% vests on the first anniversary of the February 11, 2026 grant date, and 33.3% vests on each of the second and third anniversaries, assuming continuous service on each vesting date.

What are the key terms of the 193,000 stock options granted by RPID?

The CFO’s 193,000 stock options have a $4.2 exercise price. They vest and become exercisable in 48 substantially equal monthly installments, with the first installment vesting on March 11, 2026, subject to his continued service with the company.

How many RPID Class A shares does the CFO own after these grants?

After the RSU grant, the CFO beneficially owns 580,928 Class A shares. This figure reflects his directly held Class A common stock following the February 11, 2026 award reported in the insider transaction filing.

Are the RPID equity grants to the CFO open-market purchases or awards?

The reported transactions are grants, not open-market purchases. Both the 97,000 Class A RSUs and 193,000 stock options were awarded at $0 transaction price per share as part of compensation, with vesting conditions tied to ongoing service.

When does vesting begin for the RPID CFO’s new stock option grant?

Vesting for the stock option begins on March 11, 2026. From that date, the 193,000-share option vests in 48 substantially equal monthly installments, gradually becoming exercisable over four years, contingent on his continued employment.