Cartesian Therapeutics (RNAC) director awarded RSUs and stock options

Rhea-AI Filing Summary

Cartesian Therapeutics, Inc. reported that a director received new equity awards in the form of common stock and stock options. On 12/16/2025, the director was granted 5,800 shares of common stock at a price of $0, recorded as an acquisition of non-derivative securities. Following this grant, the director beneficially owned 5,800 common shares directly.

The filing also discloses a derivative award of a stock option for 17,200 shares of common stock with an exercise price of $8.29, granted on 12/16/2025 and expiring on 12/15/2035. The 5,800-share restricted stock unit grant will vest in three equal annual installments so that all underlying shares are fully vested on December 16, 2028. The 17,200-share stock option will vest in 36 equal monthly installments and is also scheduled to be fully vested on December 16, 2028.

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^*

Bot Adrian Ion

(Last) (First) (Middle)

C/O CARTESIAN THERAPEUTICS, INC.

7495 NEW HORIZON WAY

(Street)

FREDRICK MD 21703

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Cartesian Therapeutics, Inc. [ RNAC ]

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

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

3. Date of Earliest Transaction (Month/Day/Year)
12/16/2025

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
Common Stock	12/16/2025		A(1)		5,800	A	$0	5,800	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)	$8.29	12/16/2025		A		17,200		(2)	12/15/2035	Common Stock	17,200	$0	17,200	D

Explanation of Responses:

1. Each Restricted Stock Unit represents a contingent right to receive one share of common stock, which will vest in three equal annual installments following the date of grant so that the underlying shares will be fully vested on December 16, 2028.

2. This award will vest in 36 equal monthly installments, so that it shall be fully vested on December 16, 2028.

Remarks:

	/s/ Matthew Bartholomae, Attorney-in-fact for Adrian Ion Bot	12/18/2025
	** 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).
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FAQ

What insider transaction did Cartesian Therapeutics (RNAC) report in this Form 4?

The company reported that a director acquired 5,800 shares of common stock and a stock option for 17,200 shares of common stock in equity awards dated 12/16/2025.

How many Cartesian Therapeutics (RNAC) shares were granted as restricted stock units?

The filing shows a grant of 5,800 shares of common stock through a restricted stock unit award, recorded at a price of $0.

What are the terms of the stock option granted by Cartesian Therapeutics (RNAC)?

The derivative award is a stock option to buy 17,200 shares of common stock at an exercise price of $8.29, granted on 12/16/2025 and expiring on 12/15/2035.

When do the restricted stock units for Cartesian Therapeutics (RNAC) vest?

Each restricted stock unit represents one share of common stock and will vest in three equal annual installments so that all underlying shares are fully vested on December 16, 2028.

What is the vesting schedule for the Cartesian Therapeutics (RNAC) stock options?

The 17,200-share stock option vests in 36 equal monthly installments and is scheduled to be fully vested on December 16, 2028.

Is the ownership reported in the Cartesian Therapeutics (RNAC) Form 4 direct or indirect?

The filing indicates that the 5,800 common shares and the 17,200 stock options are held with direct (D) ownership.