Cullinan officer plans sale of 8,000 shares

Cullinan Therapeutics officer Jennifer Michaelson plans to sell 8,000 CGEM shares valued at about $176,700, following earlier 10b5-1 sales.

Rhea-AI Filing Summary

Cullinan Therapeutics, Inc. (CGEM) officer Jennifer Michaelson has notified of a planned sale of 8,000 shares of common stock through Morgan Stanley Smith Barney, with an aggregate market value of $176,720.00 based on a per-share price of $64.354694 as of September 8, 2026.

The shares relate to equity awards and purchases, including stock options, restricted stock units, and employee stock purchase plan shares, and follow prior sales in recent months under a Rule 10b5-1 trading arrangement.

Key Figures

Planned shares to be sold: 8,000 shares Aggregate market value of planned sale: $176,720.00 Per-share price reference: $64.354694 per share +5 more

8 metrics

Planned shares to be sold 8,000 shares Common stock sale through Morgan Stanley Smith Barney as of September 8, 2026

Aggregate market value of planned sale $176,720.00 8,000 CGEM shares at $64.354694 per share

Per-share price reference $64.354694 per share Price used to determine market value on September 8, 2026

Shares from stock option exercise 4,000 shares Common stock from exercise of stock options on September 8, 2026

Restricted stock units 1,835 shares Common stock related to restricted stock units dated February 22, 2024

Employee Stock Purchase Plan shares 2,165 shares Common stock from employee stock purchase plan dated June 28, 2024

10b5-1 sale on August 13, 2026 30,000 shares for $607,800.00 Common stock sold under 10b5-1 for Jennifer Michaelson

10b5-1 sale on July 6, 2026 8,000 shares for $142,586.00 Common stock sold under 10b5-1 for Jennifer Michaelson

Key Terms

Rule 144, Restricted Stock Units, Employee Stock Purchase Plan, 10b5-1

4 terms

Rule 144 regulatory

"See the definition of "person" in paragraph (a) of Rule 144"

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

Restricted Stock Units financial

"Common | 02/22/2024 | Restricted Stock Units | Issuer"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

Employee Stock Purchase Plan financial

"Common | 06/28/2024 | Employee Stock Purchase Plan | Issuer"

An employee stock purchase plan is a company program that lets workers buy shares through small payroll deductions, often at a discount to the market price and after a set offering period. Think of it like a workplace savings plan that turns into ownership: it encourages employees to share in the company’s success and can create predictable buying or selling of stock that investors watch because it affects supply, demand and employee incentives.

10b5-1 regulatory

"10b5-1 Sales for JENNIFER MICHAELSON One Main Street"

A 10b5-1 plan is a pre-set schedule that lets company insiders buy or sell shares according to written instructions made when they do not possess material, nonpublic information. Think of it as a timed automatic payment for stock trades: it helps insiders avoid accusations of trading on secret information and gives outside investors a clearer signal about whether sales are routine or potentially informative about the company’s prospects.

FAQ

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

What CGEM insider transaction is Jennifer Michaelson planning?

Jennifer Michaelson, an officer of Cullinan Therapeutics, Inc. (CGEM), plans to sell 8,000 shares of common stock through Morgan Stanley Smith Barney, with an aggregate market value of $176,720.00 based on a per-share price of $64.354694 as of September 8, 2026.

What is the source of the CGEM shares Jennifer Michaelson plans to sell?

The planned CGEM share sales relate to equity awards and purchases, including an exercise of stock options for 4,000 shares on September 8, 2026, 1,835 restricted stock units dated February 22, 2024, and 2,165 employee stock purchase plan shares dated June 28, 2024.

What recent 10b5-1 CGEM sales has Jennifer Michaelson reported?

Under a Rule 10b5-1 arrangement, Jennifer Michaelson reported CGEM common stock sales of 30,000 shares on August 13, 2026 for $607,800.00 and 8,000 shares on July 6, 2026 for $142,586.00 during the past three months.

What is the reported price for the planned 8,000-share CGEM sale?

The planned sale of 8,000 CGEM shares is tied to an aggregate market value of $176,720.00, which corresponds to a per-share price of $64.354694 as of September 8, 2026.

Which broker is handling the planned CGEM share sale for Jennifer Michaelson?

The planned sale of 8,000 CGEM common shares for Jennifer Michaelson is to be handled by Morgan Stanley Smith Barney LLC Executive Financial Services, located at One New York Plaza in New York.

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

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Available on EDGAR 09/08/2026 - 04:25 PM EDT Accepted by SEC EDGAR 09/08/2026 - 04:25 PM EDT Learn about SEC filing dates

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0001838061
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	CULLINAN THERAPEUTICS, INC.
SEC File Number	001-39856
Address of Issuer	One Main Street Suite 1350 Cambridge MASSACHUSETTS 02142
Phone	6174104650
Name of Person for Whose Account the Securities are To Be Sold	JENNIFER MICHAELSON
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Officer

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common	Morgan Stanley Smith Barney LLC Executive Financial Services 1 New York Plaza 8th Floor New York NY 10004	8000	176720.00	64354694	09/08/2026	NASDAQ

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common	09/08/2026	Exercise of Stock Options	Issuer			4000	09/08/2026	Cash
Common	02/22/2024	Restricted Stock Units	Issuer			1835	02/22/2024	N/A
Common	06/28/2024	Employee Stock Purchase Plan	Issuer			2165	06/28/2024	Cash

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
10b5-1 Sales for JENNIFER MICHAELSON One Main Street Suite 1350 Cambridge MA 02142	Common	08/13/2026	30000	607800.00
10b5-1 Sales for JENNIFER MICHAELSON One Main Street Suite 1350 Cambridge MA 02142	Common	07/06/2026	8000	142586.00

144: Remarks and Signature

Remarks
Date of Notice	09/08/2026
Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1	08/07/2025
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	/s/ Jennifer Michaelson
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)