Rapid Micro Biosystems (RPID) CEO auto-sells 12,840 shares to cover RSU taxes

Rhea-AI Filing Summary

Rapid Micro Biosystems, Inc. President and CEO Robert G. Spignesi Jr. reported an automatic sale of Class A common stock. On 02/09/2026, he sold 12,840 shares at $3.7827 per share to cover tax obligations related to vesting restricted stock units. After this transaction, he beneficially owned 962,097 shares directly.

Insights

Equity compensation and insider transactions analyst

Small automatic tax-sale by CEO tied to RSU vesting appears routine.

The President and CEO of Rapid Micro Biosystems, Robert G. Spignesi Jr., executed a sale of 12,840 Class A shares at $3.7827 per share on February 9, 2026. The footnote clarifies this was an automatic sale to satisfy tax obligations from restricted stock unit vesting.

Following the transaction, Spignesi directly held 962,097 shares, indicating the sale was a small fraction of his reported holdings. Because the sale is linked to tax withholding on equity compensation rather than discretionary selling, it is typically viewed as administrative rather than a change in sentiment.

As this transaction does not alter control roles or reference any broader strategic changes, its impact on the investment thesis for Rapid Micro Biosystems is limited. Future Form 4 filings may provide additional context on ongoing equity compensation activity and overall insider ownership trends.

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

OMB Number:			3235-0287
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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^*

Spignesi Robert G. Jr.

(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)

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	PRESIDENT AND CEO

3. Date of Earliest Transaction (Month/Day/Year)
02/09/2026

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	02/09/2026		S		12,840(1)	D	$3.7827	962,097	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, Attorney-in-Fact for Robert G. Spignesi, Jr.	02/10/2026
	** 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 Rapid Micro Biosystems (RPID) report on February 9, 2026?

Rapid Micro Biosystems reported that CEO Robert G. Spignesi Jr. sold 12,840 shares of Class A common stock on February 9, 2026, at $3.7827 per share. The sale was automatically executed to cover tax obligations from vesting restricted stock units.

How many Rapid Micro Biosystems (RPID) shares does the CEO hold after the reported sale?

After the February 9, 2026 transaction, CEO Robert G. Spignesi Jr. beneficially owned 962,097 shares of Rapid Micro Biosystems Class A common stock directly. This remaining balance reflects his holdings following the automatic sale to cover taxes on vested restricted stock units.

Why did the Rapid Micro Biosystems (RPID) CEO sell 12,840 shares?

The 12,840 Rapid Micro Biosystems shares were sold automatically to cover tax obligations triggered by the vesting of restricted stock units. This type of transaction is commonly used so executives can satisfy withholding taxes without paying cash out of pocket.

Was the Rapid Micro Biosystems (RPID) CEO’s share sale a discretionary open-market trade?

No. The Form 4 states the sale represented an automatic sale of stock to cover associated tax obligations from RSU vesting. That indicates the transaction was tied to equity compensation mechanics rather than a purely discretionary decision to reduce personal holdings.

What role does Robert G. Spignesi Jr. hold at Rapid Micro Biosystems (RPID)?

Robert G. Spignesi Jr. is both President and Chief Executive Officer and a director of Rapid Micro Biosystems. His positions are disclosed in the filing, which also notes his ongoing direct ownership interest after the reported tax-related share sale on February 9, 2026.

What type of security was involved in the Rapid Micro Biosystems (RPID) Form 4 transaction?

The transaction involved Rapid Micro Biosystems Class A common stock. The Form 4 shows 12,840 shares sold at $3.7827 per share, executed as an automatic sale to fund tax withholding obligations associated with the vesting of restricted stock units awarded to the executive.