TIMOTHY A. SPRINGER - 02 Jan 2026 Form 4 Insider Report for Cartesian Therapeutics, Inc. (RNAC)

Role: Director, 10%+ Owner
Signature: /s/ Matthew Bartholomae, Attorney-in-Fact for Timothy A. Springer
Issuer symbol: RNAC
Transactions as of: 02 Jan 2026
Net transactions value: $0
Form type: 4
Filing time: 06 Jan 2026, 16:18:13 UTC
Previous filing: 11 Jun 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
SPRINGER TIMOTHY A	Director, 10%+ Owner	36 WOODMAN ROAD, CHESTNUT HILL	/s/ Matthew Bartholomae, Attorney-in-Fact for Timothy A. Springer	06 Jan 2026	0001055624

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	RNAC	Common Stock	Award	$0	+2,600	+0.03%	$0.000000	8,646,285	02 Jan 2026	Direct	F1
holding	RNAC	Common Stock						330,695	02 Jan 2026	By wife
holding	RNAC	Common Stock						656,513	02 Jan 2026	See Footnote	F2

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	RNAC	Stock Option (Right to Buy)	Award	$0	+7,800		$0.000000	7,800	02 Jan 2026	Common Stock	7,800	$6.76	Direct

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	Each Restricted Stock Unit represents a contingent right to receive one share of common stock, which will vest in full on January 2, 2027.
F2	Held by TAS Partners LLC. The reporting person is the managing member of TAS Partners LLC. The reporting person disclaims beneficial ownership of the securities held by TAS Partners LLC except to the extent of his pecuniary interest therein, if any.