Cullinan Therapeutics (CGEM) CSO sells 5,353 shares under 10b5-1 plan

Rhea-AI Filing Summary

Cullinan Therapeutics, Inc. Chief Scientific Officer Jennifer Michaelson reported selling a total of 5,353 shares of common stock in open-market transactions. She sold 3,601 shares on February 24, 2026 at a weighted average price of $14.47 per share and 1,752 shares on February 23, 2026 at a weighted average price of $13.99 per share. These sales were effected under a Rule 10b5-1 trading plan and were described as covering personal income tax obligations upon vesting of restricted stock units. After the transactions, she directly holds 176,624 Cullinan Therapeutics common shares.

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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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)
02/23/2026

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	02/23/2026		S(1)		1,752	D	$13.99(2)	180,225	D
Common Stock	02/24/2026		S(3)		3,601	D	$14.47	176,624	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. Transaction effected pursuant to a plan established pursuant to Rule 10b5-1 on August 7, 2025.

2. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $13.68 to $14.31. 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.

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

	/s/ Jacquelyn Sumer, Attorney-in-Fact	02/25/2026
	** 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.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What insider transaction did Cullinan Therapeutics (CGEM) report for its CSO?

Cullinan Therapeutics Chief Scientific Officer Jennifer Michaelson reported open-market sales of company common stock. She filed a Form 4 detailing two sales totaling 5,353 shares, executed on February 23 and 24, 2026, under a pre-established Rule 10b5-1 trading plan.

How many CGEM shares did Jennifer Michaelson sell and at what prices?

Jennifer Michaelson sold 5,353 Cullinan Therapeutics common shares in total. She sold 1,752 shares at a weighted average price of $13.99 on February 23, 2026, and 3,601 shares at a weighted average price of $14.47 on February 24, 2026, in open-market transactions.

Was the Cullinan Therapeutics CSO sale made under a Rule 10b5-1 plan?

Yes. The Form 4 notes the transactions were effected under a Rule 10b5-1 trading plan established on August 7, 2025. Such plans automatically schedule trades in advance, aiming to separate personal trading decisions from day-to-day company developments and potential nonpublic information.

Why did Cullinan Therapeutics CSO Jennifer Michaelson sell CGEM shares?

A footnote explains the sale was to cover personal income tax obligations arising when restricted stock units vested. This indicates the transactions were linked to equity compensation and related tax liabilities, rather than described as discretionary portfolio sales in the filing language.

How many Cullinan Therapeutics (CGEM) shares does the CSO hold after the sale?

After completing the reported transactions, Jennifer Michaelson directly holds 176,624 shares of Cullinan Therapeutics common stock. This post-transaction ownership figure is disclosed in the Form 4 as the number of shares beneficially owned following the February 24, 2026 sale.

What is the total net share change from this Cullinan Therapeutics Form 4?

The Form 4 reflects a net sale of 5,353 Cullinan Therapeutics shares by the reporting person. All reported transactions were coded as open-market sales, with no corresponding purchases or acquisitions, resulting in a net reduction of her directly held common stock position.