Rapid Micro (RPID) director granted RSUs and stock options

Rhea-AI Filing Summary

RAPID MICRO BIOSYSTEMS, INC. director Inese Lowenstein reported new equity compensation awards. She received 19,300 shares of Class A common stock as restricted stock units that vest in full on the earlier of the first anniversary of the grant date or the day immediately prior to the next annual stockholder meeting, provided she remains in continuous service.

She was also granted a stock option for 38,700 shares of Class A common stock at an exercise price of $2.07 per share, with the option vesting on the same schedule. After the grant, she directly holds 57,900 shares of Class A common stock and 38,700 options.

Insider Trade Summary

2 transactions reported

Mixed 2 txns

Insider LOWENSTEIN INESE

Role null

Type	Security	Shares	Price	Value
Grant/Award	Stock Option (Right to Buy)	38,700	$0.00	--
Grant/Award	Class A Common Stock	19,300	$0.00	--

Holdings After Transaction: Stock Option (Right to Buy) — 38,700 shares (Direct, null); Class A Common Stock — 57,900 shares (Direct, null)

Footnotes (1)

1. Grant of restricted stock units ("RSUs") that vests in full on the earlier of (i) the first anniversary of the Grant Date, or (ii) the day immediately prior to the date of the next annual meeting of the stockholders of the Company provided that the Reporting Person remains in continuous service on such vesting date. The option shall vest and become exercisable in full on the earlier of (i) the first anniversary of the Grant Date, or (ii) the day immediately prior to the date of the next annual meeting of the stockholders of the Company provided that the Reporting Person remains in continuous service on such vesting date.

Key Figures

RSU grant: 19,300 shares Option grant size: 38,700 options Option exercise price: $2.07 per share +3 more

6 metrics

RSU grant 19,300 shares Restricted stock units granted to director on May 21, 2026

Option grant size 38,700 options Stock option award to director on May 21, 2026

Option exercise price $2.07 per share Exercise price for 38,700-share stock option

Option expiration May 20, 2036 Expiration date of granted stock option

Shares after grant 57,900 shares Total Class A common shares directly held after RSU grant

Options after grant 38,700 options Total stock options directly held following transaction

Key Terms

restricted stock units ("RSUs"), Stock Option (Right to Buy), continuous service, annual meeting of the stockholders

4 terms

restricted stock units ("RSUs") financial

"Grant of restricted stock units ("RSUs") that vests in full on the earlier of"

Restricted stock units (RSUs) are a company promise to give an employee shares of stock (or cash equivalent) in the future, but only after certain conditions—usually staying with the company for a set time or hitting performance goals—are met. Investors watch RSUs because when they vest they increase the number of shares outstanding and can lead insiders to sell shares, affecting share price, company dilution and the true cost of employee pay.

Stock Option (Right to Buy) financial

"Stock Option (Right to Buy) with underlying security Class A Common Stock"

continuous service financial

"provided that the Reporting Person remains in continuous service on such vesting date."

annual meeting of the stockholders financial

"the day immediately prior to the date of the next annual meeting of the stockholders of the Company"

Form 4 Insider Transactions: What Each Field Means →

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
Estimated average burden
hours per response:			0.5

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^*

LOWENSTEIN INESE

(Last) (First) (Middle)

C/O RAPID MICRO BIOSYSTEMS, INC.

25 HARTWELL AVENUE

(Street)

LEXINGTON MASSACHUSETTS 02421

(City) (State) (Zip)

UNITED STATES

(Country)

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
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/21/2026

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

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

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

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	05/21/2026		A		19,300(1)	A	$0	57,900	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)	$2.07	05/21/2026		A		38,700		(2)	05/20/2036	Class A Common Stock	38,700	$0	38,700	D

Explanation of Responses:

1. Grant of restricted stock units ("RSUs") that vests in full on the earlier of (i) the first anniversary of the Grant Date, or (ii) the day immediately prior to the date of the next annual meeting of the stockholders of the Company provided that the Reporting Person remains in continuous service on such vesting date.

2. The option shall vest and become exercisable in full on the earlier of (i) the first anniversary of the Grant Date, or (ii) the day immediately prior to the date of the next annual meeting of the stockholders of the Company provided that the Reporting Person remains in continuous service on such vesting date.

Remarks:

	/s/ Robert Spignesi, Attorney-in-Fact for Inese Lowenstein	05/26/2026
	** 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.
* Form 4: SEC 1474 (03-26)

FAQ

What equity awards did RPID director Inese Lowenstein receive?

Inese Lowenstein received 19,300 restricted stock units and a stock option for 38,700 shares of Rapid Micro Biosystems Class A common stock at $2.07 per share. These awards increase her direct equity stake and potential future ownership in the company.

When do Inese Lowenstein’s new RPID RSUs and options vest?

Both the 19,300 restricted stock units and the 38,700-share stock option vest in full on the earlier of the first anniversary of the grant date or the day immediately before the next annual stockholder meeting, assuming she remains in continuous service until that vesting date.

What is the exercise price and term of Inese Lowenstein’s new RPID stock option?

The new stock option covers 38,700 shares of Class A common stock at an exercise price of $2.07 per share. The option expires on May 20, 2036, giving a long window for potential exercise once it has fully vested.

How many Rapid Micro Biosystems shares does Inese Lowenstein hold after these grants?

Following the grants, Inese Lowenstein directly holds 57,900 shares of Rapid Micro Biosystems Class A common stock. She also holds a stock option for 38,700 additional shares, which may be exercisable after vesting according to the disclosed schedule.

Are Inese Lowenstein’s RPID awards open-market purchases or compensation grants?

The filing characterizes both transactions as compensation-related grants. The 19,300 shares are restricted stock units and the 38,700-share option is a stock option award, each reported with transaction code A for grant, award, or other acquisition rather than open-market buying.