Cullinan Therapeutics (CGEM) Chief Scientific Officer logs insider share sales

Rhea-AI Filing Summary

Cullinan Therapeutics Chief Scientific Officer, a reporting officer of the company, disclosed small open-market stock sales in December 2025. On 12/12/2025, 2,148 shares of common stock were sold at $12.38 to cover personal income tax obligations related to vesting restricted stock units.

On 12/15/2025, 995 shares were sold at $11.90 under a pre-arranged trading plan established pursuant to Rule 10b5-1 on August 7, 2025. After these transactions, the officer beneficially owns 136,878 shares of common stock, including 2,017 shares purchased through the 2021 Employee Stock Purchase Plan for the purchase period from January 1, 2025 through June 30, 2025.

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

OMB APPROVAL

OMB Number:			3235-0287
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hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

X

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^*

Michaelson Jennifer

(Last) (First) (Middle)

C/O CULLINAN THERAPEUTICS, INC.

ONE MAIN STREET, SUITE 1350

(Street)

CAMBRIDGE MA 02142

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Cullinan Therapeutics, Inc. [ CGEM ]

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

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

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

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	12/12/2025		S(1)		2,148	D	$12.38	137,873(2)	D
Common Stock	12/15/2025		S(3)		995	D	$11.9	136,878	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

Explanation of Responses:

1. Sale of shares to cover personal income tax obligations upon vesting of restricted stock units.

2. Includes 2,017 shares of common stock that the Reporting Person purchased pursuant to the Issuer's 2021 Employee Stock Purchase Plan for the purchase period of January 1, 2025 through June 30, 2025 that were exempt under both Rule 16b-3(d) and Rule 16b-3(c).

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

	/s/ Jacquelyn Sumer, Attorney-in-Fact	12/16/2025
	** 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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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FAQ

What insider transactions did Cullinan Therapeutics (CGEM) report in this Form 4?

The Chief Scientific Officer of Cullinan Therapeutics reported two sales of common stock in December 2025: 2,148 shares sold on 12/12/2025 and 995 shares sold on 12/15/2025.

Who is the reporting person and what is their role at Cullinan Therapeutics (CGEM)?

The reporting person is an officer of Cullinan Therapeutics serving as the Chief Scientific Officer, as indicated in the relationship section of the report.

At what prices were the Cullinan Therapeutics (CGEM) shares sold in December 2025?

On 12/12/2025, 2,148 shares of common stock were sold at $12.38 per share, and on 12/15/2025, 995 shares were sold at $11.90 per share.

How many Cullinan Therapeutics (CGEM) shares does the officer beneficially own after these transactions?

Following the reported sales, the Chief Scientific Officer beneficially owns 136,878 shares of Cullinan Therapeutics common stock.

What portion of the Cullinan Therapeutics (CGEM) holdings came from the Employee Stock Purchase Plan?

The beneficial ownership figure includes 2,017 shares of common stock that were purchased under the companys 2021 Employee Stock Purchase Plan for the period from January 1, 2025 through June 30, 2025.

Was any Cullinan Therapeutics (CGEM) trade made under a Rule 10b5-1 plan?

Yes. The 995-share sale on 12/15/2025 was effected pursuant to a trading plan established under Rule 10b5-1 on August 7, 2025, which is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

Why were some Cullinan Therapeutics (CGEM) shares sold on 12/12/2025?

The 2,148 shares sold on 12/12/2025 were disposed of to cover personal income tax obligations arising when certain restricted stock units vested.