Cullinan director granted options on 25,319 shares

Cullinan Therapeutics director Stephen W. Webster received a stock option grant covering 25,319 shares of common stock.

Rhea-AI Filing Summary

Cullinan Therapeutics director Stephen W. Webster received a stock option grant covering 25,319 shares of common stock. The option has an exercise price of $13.55 per share and was awarded as compensation, not an open-market purchase or sale. It vests in full on the earlier of June 16, 2027 or the company’s next annual meeting, contingent on his continued board service. Following this grant, Webster holds options for 25,319 underlying shares.

Insider Trade Summary

Grant/Award: 25,319 shares

Grant/Award 1 txn

Insider Webster Stephen W

Role Director

Type	Security	Shares	Price	Value
Grant/Award	Stock Option (Right to Buy)	25,319	$0.00	$0.00

Holdings After Transaction: Stock Option (Right to Buy) — 25,319 contracts (Direct)

Footnotes (1)

1. F1. The option represents a right to purchase a total of 25,319 shares of the Issuer's Common Stock, which shall vest in full on the earlier of (i) June 16, 2027 or (ii) the date of the Issuer's next annual meeting, subject to the Reporting Person's continued service as a director on such vesting date.

Key Figures

Option grant size: 25,319 shares Exercise price: $13.55 per share Options after grant: 25,319 derivative securities +2 more

5 metrics

Option grant size 25,319 shares Underlying common stock covered by new stock option award

Exercise price $13.55 per share Conversion or exercise price of the stock option

Options after grant 25,319 derivative securities Total option securities following the reported transaction

Grant date June 16, 2026 Transaction date for the stock option award

Stated expiration date June 16, 2026 Expiration date field for the reported option

Key Terms

Stock Option (Right to Buy), Common Stock, vesting, Form 4

4 terms

Stock Option (Right to Buy) financial

"security_title: "Stock Option (Right to Buy)""

Common Stock financial

"underlying_security_title: "Common Stock""

Common stock represents ownership shares in a company, giving investors a stake in its success and a say in important decisions through voting rights. It is the most common type of stock traded on markets and can provide income through dividends, as well as potential for value growth. For investors, holding common stock means sharing in the company’s profits and risks.

vesting financial

"which shall vest in full on the earlier of (i) June 16, 2027"

Vesting is the process by which you earn full ownership of something, like company stock or a retirement benefit, over time. It’s like earning the right to keep a gift piece by piece the longer you stay with a company, making sure employees stay committed before they receive all the benefits.

Form 4 regulatory

"INSIDER FILING DATA (Form 4):"

Form 4 is a official document that company insiders, such as executives or major shareholders, file with regulators whenever they buy or sell company shares. It provides transparency about how those with inside knowledge are trading, helping investors see if insiders are confident in the company's prospects or may be selling for personal reasons. This information can influence investor decisions by revealing insiders' perspectives on the company's value.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What did Cullinan Therapeutics (CGEM) director Stephen W. Webster report on this Form 4?

Stephen W. Webster reported receiving a stock option grant for 25,319 shares of Cullinan Therapeutics common stock. The award is compensation, not an open-market trade, and gives him the right to buy shares at a fixed exercise price if the option vests.

How many Cullinan Therapeutics (CGEM) shares are covered by Stephen Webster’s new option grant?

The new option grant covers 25,319 underlying shares of Cullinan Therapeutics common stock. This represents the entire number of shares tied to the reported award and equals his total option holdings following this transaction, according to the Form 4 details.

What is the exercise price of Stephen Webster’s Cullinan Therapeutics (CGEM) stock options?

The option has an exercise price of $13.55 per share for Cullinan Therapeutics common stock. This means Webster can choose to buy shares at $13.55 if and when the option vests and is exercised, regardless of the future market price at that time.

When do Stephen Webster’s Cullinan Therapeutics (CGEM) options vest?

The options vest in full on the earlier of June 16, 2027 or the date of Cullinan Therapeutics’ next annual meeting. Vesting is conditioned on Webster continuing to serve as a director through that vesting date, as described in the Form 4 footnote.

Is Stephen Webster buying or selling Cullinan Therapeutics (CGEM) shares in this Form 4?

This Form 4 does not show Webster buying or selling shares in the market. It reports a grant of stock options as compensation, giving him the right to purchase 25,319 shares later, subject to vesting, rather than an immediate stock trade.

How many Cullinan Therapeutics (CGEM) option shares does Stephen Webster hold after this grant?

After the reported transaction, Webster holds options tied to 25,319 underlying shares of Cullinan Therapeutics common stock. The Form 4 lists 25,319 derivative securities following the transaction, matching the full size of the newly granted award.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 06/18/2026 - 05:00 PM EDT Learn about SEC filing dates

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
Estimated average burden
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).

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^*

Webster Stephen W

(Last) (First) (Middle)

C/O CULLINAN THERAPEUTICS, INC.

ONE MAIN STREET, SUITE 1350

(Street)

CAMBRIDGE MASSACHUSETTS 02142

(City) (State) (Zip)

UNITED STATES

(Country)

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

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
06/16/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

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

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
Stock Option (Right to Buy)	$13.55	06/16/2026		A		25,319		(1)	06/16/2026	Common Stock	25,319	$0	25,319	D

Explanation of Responses:

1. The option represents a right to purchase a total of 25,319 shares of the Issuer's Common Stock, which shall vest in full on the earlier of (i) June 16, 2027 or (ii) the date of the Issuer's next annual meeting, subject to the Reporting Person's continued service as a director on such vesting date.

	/s/ Jacquelyn Sumer, Attorney-in-Fact	06/18/2026
	** 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.
* Form 4: SEC 1474 (03-26)