STOCK TITAN

Cullinan Therapeutics (NASDAQ: CGEM) CSO sells 8,000 shares, exercises 4,000 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 a total of 8,000 shares of Common Stock in open-market transactions at weighted average prices of $14.60 and $15.58, with actual trade prices ranging from $14.24 to $15.60. These sales were executed pursuant to a pre-established Rule 10b5-1 trading plan dated August 7, 2025. On the same day, she exercised stock options for 4,000 shares of Common Stock at an exercise price of $4.30 per share, converting a derivative position into additional common shares while using part of her holdings for liquidity.

Positive

  • None.

Negative

  • None.
Insider Michaelson Jennifer
Role Chief Scientific Officer
Sold 8,000 shs ($117K)
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 7,800 $14.60 $114K
Sale Common Stock 200 $15.58 $3K
Holdings After Transaction: Stock Option (Right to Buy) — 116,987 shares (Direct, null); Common Stock — 174,844 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 $14.24 to $15.12. 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. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $15.56 to $15.60. 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 Open-market sales of Common Stock on May 5, 2026
Weighted average sale price block 1 $14.60 per share 7,800-share sale block on May 5, 2026
Weighted average sale price block 2 $15.58 per share 200-share sale block on May 5, 2026
Sale price range $14.24–$15.60 Multiple transactions across this intraday range
Options exercised 4,000 shares Stock Option (Right to Buy) converted into Common Stock
Option exercise price $4.30 per share Exercise price for 4,000-share stock option
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 (Right to Buy) financial
"security_title": "Stock Option (Right to Buy)""
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.
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.
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)
05/05/2026
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 Stock05/05/2026M4,000A$4.3174,844D
Common Stock05/05/2026S(1)7,800D$14.6(2)167,044D
Common Stock05/05/2026S(1)200D$15.58(3)166,844D
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)$4.305/05/2026M4,000 (4)10/28/2030Common Stock4,000$0116,987D
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 $14.24 to $15.12. 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. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $15.56 to $15.60. 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.
4. 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-Fact05/06/2026
** 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)

FAQ

What insider transactions did CGEM’s Chief Scientific Officer report on this Form 4?

Cullinan Therapeutics’ Chief Scientific Officer, Jennifer Michaelson, reported selling 8,000 shares of Common Stock and exercising stock options for 4,000 shares at $4.30 per share, combining an option exercise with open-market sales.

At what prices did Jennifer Michaelson sell Cullinan Therapeutics (CGEM) shares?

She reported weighted average sale prices of $14.60 and $15.58 per share. Footnotes state the actual trades occurred in multiple transactions at prices ranging from $14.24 to $15.60, reflecting typical execution across an intraday price range.

How many Cullinan Therapeutics (CGEM) shares did the CSO sell in this Form 4?

The filing shows open‑market sales totaling 8,000 shares of Cullinan Therapeutics Common Stock. These sales are split between 200 shares at a weighted average price of $15.58 and 7,800 shares at a weighted average price of $14.60.

What stock options did Jennifer Michaelson exercise in the CGEM Form 4 filing?

She exercised a Stock Option (Right to Buy) covering 4,000 shares of Cullinan Therapeutics Common Stock at an exercise price of $4.30 per share. This converted a derivative position into additional common shares as part of a broader exercise‑and‑sell pattern.

Was the CGEM insider sale by the Chief Scientific Officer under a Rule 10b5-1 plan?

Yes. A footnote states the transactions were effected pursuant to a Rule 10b5‑1 trading plan established on August 7, 2025. Such pre‑arranged plans automate trades over time, reducing the significance of short‑term timing decisions.

How does this Cullinan Therapeutics (CGEM) Form 4 classify the insider transactions?

The filing classifies the 8,000‑share dispositions as open‑market sales with code S and the 4,000‑share option event as an exercise or conversion of a derivative security with code M. Both positions are reported as direct ownership.