Jennifer Michaelson - 13 Aug 2026 Form 4 Insider Report for Cullinan Therapeutics, Inc. (CGEM)

Reporting relationship: Chief Scientific Officer
Issuer ticker: CGEM
Reported as of: 13 Aug 2026
Net transaction value: -$607,800
SEC form: 4
Accepted by SEC: 14 Aug 2026, 17:00:06 UTC
Prior SEC filing: 07 Jul 2026
Source filing: View source filing
Reporting owner signature: /s/ Jacquelyn Sumer, Attorney-in-Fact

Key filing fact

Jennifer Michaelson filed Form 4 for Cullinan Therapeutics, Inc. (CGEM) on 14 Aug 2026.

Key facts

This page summarizes Jennifer Michaelson's Form 4 filing for Cullinan Therapeutics, Inc. (CGEM).
3 reported transactions and 1 derivative row are listed below.
Accepted by SEC: 14 Aug 2026, 17:00.

Change

Previous filing in this sequence was filed on 07 Jul 2026.
Current net transaction value: -$607,800.

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 0001838061 Primary reporting owner

Michaelson Jennifer

Relationship: Chief Scientific Officer
Address: C/O CULLINAN THERAPEUTICS, INC., ONE MAIN STREET, SUITE 1350, CAMBRIDGE
Signature: /s/ Jacquelyn Sumer, Attorney-in-Fact
Signature date: 14 Aug 2026

Reported non-derivative transactions

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

CGEM transaction

Common Stock

Options Exercise

Transaction value
Shares: +30,000
Change %: +18%
Price: $4.30^*
Shares after: 192,844
Date: 13 Aug 2026
Ownership: Direct

CGEM transaction

Common Stock

Sale

Transaction value: $607,800
Shares: -30,000
Change %: -16%
Price: $20.26
Shares after: 162,844
Date: 13 Aug 2026
Ownership: Direct
Footnotes: F1, F2

Reported derivative securities

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

CGEM transaction Derivative

Stock Option (Right to Buy)

Options Exercise

Transaction value
Shares: -30,000
Change %: -27%
Price: $0.000000^*
Shares after: 82,987
Date: 13 Aug 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 30,000
Exercise price: $4.30
Footnotes: F3

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

Additional SEC filing notes

Filing notes and footnotes

Rule 10b5-1 trading plan

These transactions were reported as open-market trades under a Rule 10b5-1 plan. The plan lets an insider set trading instructions in advance, which can reduce the risk of trading while in possession of material nonpublic information.

Original filing language: transaction made pursuant to a contract, instruction, or written plan intended to satisfy Rule 10b5-1(c).

Explanation of responses 3 footnotes

Footnote F1

Transaction effected pursuant to a plan established pursuant to Rule 10b5-1 on August 7, 2025.

Footnote F2

The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $20.00 to $20.69. The Reporting Person undertakes to provide to the Issuer, any shareholder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

Footnote F3

25% of the shares vested on July 4, 2020, and the remaining shares vested in 36 equal monthly installments thereafter.