Rapid Micro (RPID) CFO sells shares to cover RSU tax obligations

Rhea-AI Filing Summary

RAPID MICRO BIOSYSTEMS, INC. Chief Financial Officer Sean M. Wirtjes reported an automatic sale of Class A common stock to cover taxes tied to restricted stock unit vesting. He sold 17,254 shares at an average price of $3.923 per share. After this tax-related sale, he continues to hold 563,674 shares directly.

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

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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)
02/20/2026

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	02/20/2026		S		17,254(1)	D	$3.923	563,674	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

Explanation of Responses:

1. Represents the automatic sale of stock to cover the associated tax obligations with the vesting of restricted stock units.

Remarks:

	/s/ Sean M. Wirtjes	02/20/2026
	** 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 insider transaction did RPID CFO Sean Wirtjes report?

Sean Wirtjes reported an automatic sale of 17,254 Class A common shares. The shares were sold at an average price of $3.923 each to cover tax obligations arising from restricted stock unit vesting, according to the footnote disclosure.

Was the RPID CFO’s stock sale a discretionary open-market trade?

The sale was not discretionary; it was automatic to cover taxes. A filing footnote explains the 17,254 shares were sold solely to satisfy tax obligations from vesting restricted stock units, rather than being an elective open-market sale.

How many RPID shares does the CFO hold after this transaction?

Following the tax-related sale, Sean Wirtjes holds 563,674 Class A common shares directly. This post-transaction balance shows he retains a substantial equity position in Rapid Micro Biosystems even after covering the associated tax obligations.

What price did RPID shares sell for in the CFO’s Form 4 filing?

The reported sale price was an average of $3.923 per share for 17,254 Class A common shares. This price reflects the transaction used to cover tax obligations linked to the vesting of restricted stock units, as described in the footnote.

What does the Form 4 footnote say about the RPID CFO’s sale?

The footnote explains the sale represents an automatic sale of stock to cover tax obligations related to restricted stock unit vesting. This indicates the transaction was driven by tax withholding needs rather than a discretionary decision to reduce holdings.

Does the RPID CFO’s Form 4 indicate buying or selling activity overall?

The Form 4 reflects net selling activity, specifically a single sale of 17,254 shares. No purchases or other acquisitions were reported, and the transaction summary shows one sale transaction and a net-sell share direction for this filing.