Carsten Brunn - 02 Jan 2026 Form 4 Insider Report for Cartesian Therapeutics, Inc. (RNAC)

Reporting relationship: President and CEO, Director
Issuer ticker: RNAC
Reported as of: 02 Jan 2026
Net transaction value: $0
SEC form: 4
Accepted by SEC: 06 Jan 2026, 16:19:20 UTC
Prior SEC filing: 07 Jan 2025
Next SEC filing: 08 Jan 2026
Source filing: View source filing
Reporting owner signature: /s/ Matthew Bartholomae, Attorney-in-Fact for Carsten Brunn

Key filing fact

Carsten Brunn filed Form 4 for Cartesian Therapeutics, Inc. (RNAC) on 06 Jan 2026.

Key facts

This page summarizes Carsten Brunn'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, 16:19.

Change

Previous filing in this sequence was filed on 07 Jan 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 0001760229 Primary reporting owner

Brunn Carsten

Relationship: President and CEO, Director
Address: C/O CARTESIAN THERAPEUTICS, INC., 7495 NEW HORIZON WAY, FREDERICK
Signature: /s/ Matthew Bartholomae, Attorney-in-Fact for Carsten Brunn
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: +143,200
Change %: +70%
Price: $0.000000
Shares after: 347,296
Date: 02 Jan 2026
Ownership: Direct
Footnotes: F1

Reported derivative securities

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

RNAC transaction Derivative

Employee Stock Option (right to buy)

Award

Transaction value: $0
Shares: +415,700
Change %
Price: $0.000000
Shares after: 415,700
Date: 02 Jan 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 415,700
Exercise price: $6.76
Footnotes: F2

^* 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 as to 25% on January 2, 2027. The remainder of the underlying shares will vest in three equal annual installments thereafter so that the underlying shares will be fully vested on January 2, 2030.

Footnote F2

This option vests as to 25% on January 2, 2027. The remainder of the underlying shares will vest in 36 equal monthly installments thereafter.