STOCK TITAN

Cullinan Therapeutics (CGEM) CSO sells shares, exercises stock options

Filing Impact
(Moderate)
Filing Sentiment
(Negative)
Form Type
4

Rhea-AI Filing Summary

Cullinan Therapeutics Chief Scientific Officer Jennifer Michaelson reported an exercise-and-sell transaction in company stock. She sold 8,000 shares of common stock in an open-market sale at a weighted average price of $17.82 per share, executed under a pre-arranged Rule 10b5-1 trading plan established on August 7, 2025. On the same date, she exercised stock options for 4,000 shares of common stock at an exercise price of $4.30 per share. After these transactions, she directly owned 162,844 shares of Cullinan Therapeutics common stock and held 112,987 stock options exercisable at $4.30 per share, which expire on October 28, 2030.

Positive

  • None.

Negative

  • None.
Insider Michaelson Jennifer
Role Chief Scientific Officer
Sold 8,000 shs ($143K)
Type Security Shares Price Value
Exercise Stock Option (Right to Buy) 4,000 $0.00 --
Exercise Common Stock 4,000 $4.30 $17K
Sale Common Stock 8,000 $17.82 $143K
Holdings After Transaction: Stock Option (Right to Buy) — 112,987 shares (Direct, null); Common Stock — 170,844 shares (Direct, null)
Footnotes (1)
  1. Transaction effected pursuant to a plan established pursuant to Rule 10b5-1 on August 7, 2025. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $17.35 to $18.19. 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. 25% of the shares vested on July 4, 2020, and the remaining shares vested in 36 equal monthly installments thereafter.
Shares sold 8,000 shares Common stock open-market sale on July 6, 2026 at $17.82
Sale price $17.82 per share Weighted average sale price for 8,000 shares
Options exercised 4,000 shares Common stock obtained via option exercise on July 6, 2026
Exercise price $4.30 per share Stock option exercise price for 4,000 shares
Shares held after 162,844 shares Common stock directly owned after transactions
Remaining options 112,987 options Stock options outstanding after exercise at $4.30
Option expiration October 28, 2030 Expiration date of the reported stock options
Rule 10b5-1 regulatory
"Transaction effected pursuant to a plan established pursuant to Rule 10b5-1 on August 7, 2025."
Rule 10b5-1 is a regulation that allows company insiders to buy or sell their shares at predetermined times, even if they have access to non-public information. It acts like setting a schedule in advance for transactions, helping prevent accusations of unfair trading. This rule provides a way for insiders to plan trades transparently, giving investors confidence that these transactions are not based on hidden information.
weighted average price financial
"The price reported in Column 4 is a weighted average price."
Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.
stock option financial
"Stock Option (Right to Buy)"
A stock option is a contract that gives you the right to buy or sell a company's stock at a specific price within a certain time frame. People use them to potentially make money if the stock's price moves favorably or to protect against losses. It's like holding a coupon that can be used to buy or sell stock at a set price later on.
open-market sale financial
"transaction_action":"open-market sale""
An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.
derivative security financial
"Exercise or conversion of derivative security"
A derivative security is a financial contract whose value comes from the price or performance of something else, such as a stock, bond, commodity, or market index. For investors it acts like an insurance policy or a wager: it can be used to protect against losses, lock in prices, or amplify gains and losses, so it can change a portfolio’s risk and potential return without owning the underlying asset directly.
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FAQ

What insider transactions did Cullinan Therapeutics (CGEM) report for Jennifer Michaelson?

Cullinan Therapeutics reported that Chief Scientific Officer Jennifer Michaelson sold 8,000 shares of common stock and exercised options for 4,000 shares. Both transactions occurred on July 6, 2026 as part of a disclosed trading pattern in the company’s stock.

How many Cullinan Therapeutics (CGEM) shares did Jennifer Michaelson sell and at what price?

Jennifer Michaelson sold 8,000 shares of Cullinan Therapeutics common stock at a weighted average price of $17.82 per share. The sales occurred in multiple trades between $17.35 and $18.19, according to the disclosed price range in the filing’s footnote.

What stock options did Jennifer Michaelson exercise in the Cullinan Therapeutics (CGEM) Form 4?

She exercised stock options covering 4,000 shares of Cullinan Therapeutics common stock at an exercise price of $4.30 per share. These options vested over time, with 25% vesting July 4, 2020 and the remainder in 36 equal monthly installments thereafter.

How many Cullinan Therapeutics (CGEM) shares does Jennifer Michaelson hold after these transactions?

Following the reported sale and option exercise, Jennifer Michaelson directly holds 162,844 shares of Cullinan Therapeutics common stock. This figure reflects her updated ownership position after all transactions disclosed in the Form 4 for the July 6, 2026 trading date.

Were Jennifer Michaelson’s Cullinan Therapeutics (CGEM) share sales under a Rule 10b5-1 plan?

Yes. The filing states the transaction was effected under a Rule 10b5-1 trading plan established on August 7, 2025. Such plans pre-schedule trades, indicating the timing of the July 6, 2026 sales was determined in advance rather than chosen opportunistically.

What Cullinan Therapeutics (CGEM) stock options remain for Jennifer Michaelson after the Form 4 transactions?

After exercising 4,000 options, Jennifer Michaelson holds 112,987 remaining stock options with an exercise price of $4.30 per share. These options are reported to expire on October 28, 2030, providing a long-dated potential source of additional common shares.
SEC Form 4
FORM 4UNITED 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).
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 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)
Director10% Owner
XOfficer (give title below)Other (specify below)
Chief Scientific Officer
2a. Foreign Trading Symbol
3. Date of Earliest Transaction (Month/Day/Year)
07/06/2026
6. Individual or Joint/Group Filing (Check Applicable Line)
XForm 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)
CodeVAmount(A) or (D)Price
Common Stock07/06/2026M4,000A$4.3170,844D
Common Stock07/06/2026S(1)8,000D$17.82(2)162,844D
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)
CodeV(A)(D)Date ExercisableExpiration DateTitleAmount or Number of Shares
Stock Option (Right to Buy)$4.307/06/2026M4,000 (3)10/28/2030Common Stock4,000$0112,987D
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 $17.35 to $18.19. 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. 25% of the shares vested on July 4, 2020, and the remaining shares vested in 36 equal monthly installments thereafter.
/s/ Jacquelyn Sumer, Attorney-in-Fact07/07/2026
** Signature of Reporting PersonDate
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)