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

Reporting relationship: Director, 10%+ Owner
Issuer ticker: RNAC
Reported as of: 02 Jan 2026
Net transaction value: $0
SEC form: 4
Accepted by SEC: 06 Jan 2026, 16:18:13 UTC
Prior SEC filing: 11 Jun 2025
Next SEC filing: 10 Jun 2026
Source filing: View source filing
Reporting owner signature: /s/ Matthew Bartholomae, Attorney-in-Fact for Timothy A. Springer

Key filing fact

Timothy A. Springer filed Form 4 for Cartesian Therapeutics, Inc. (RNAC) on 06 Jan 2026.

Key facts

This page summarizes Timothy A. Springer's Form 4 filing for Cartesian Therapeutics, Inc. (RNAC).
2 reported transactions and 1 derivative row are listed below.
Accepted by SEC: 06 Jan 2026, 16:18.

Change

Previous filing in this sequence was filed on 11 Jun 2025.
Current net transaction value: $0.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001055624 Primary reporting owner

SPRINGER TIMOTHY A

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

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

RNAC transaction

Common Stock

Award

Transaction value: $0
Shares: +2,600
Change %: +0.03%
Price: $0.000000
Shares after: 8,646,285
Date: 02 Jan 2026
Ownership: Direct
Footnotes: F1

RNAC holding

Common Stock

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after: 330,695
Date: 02 Jan 2026
Ownership: By wife

RNAC holding

Common Stock

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after: 656,513
Date: 02 Jan 2026
Ownership: See Footnote
Footnotes: F2

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

RNAC transaction Derivative

Stock Option (Right to Buy)

Award

Transaction value: $0
Shares: +7,800
Change %
Price: $0.000000
Shares after: 7,800
Date: 02 Jan 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 7,800
Exercise price: $6.76

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 2 footnotes

Footnote 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.

Footnote 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.