[Form 4] Tourmaline Bio, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Aaron Kantoff, a director of Tourmaline Bio, Inc. (TRML), reported option exercises on 09/05/2025 that resulted in the acquisition of common stock. He exercised options to acquire 37,890 shares at an exercise price of $0.13 per share and 10,000 shares at $9.46 per share on that date. After these reported transactions the filing shows 93,281 shares beneficially owned by Mr. Kantoff on a direct basis. The filing is signed by an attorney-in-fact on behalf of the reporting person.

The filing notes the exercised options are fully vested and immediately exercisable. Transaction code "M" is recorded for both entries and the filing is a standalone Form 4 by one reporting person for TRML.

Positive

• Reporting person acquired 37,890 shares at $0.13 and 10,000 shares at $9.46 through option exercises on 09/05/2025.
• The filing states the options were fully vested and immediately exercisable, and the report was filed by one reporting person.
• Post-transaction direct beneficial ownership is 93,281 shares as reported on the Form 4.

Negative

• None.

Insights

Corporate Governance Expert

TL;DR: Director exercised vested options and increased direct shareholdings to 93,281 shares.

The Form 4 documents two option exercises by a Tourmaline Bio director on 09/05/2025. Both exercises are reported with transaction code M and the filing explicitly states the options were fully vested and immediately exercisable. The exercises converted 47,890 option units into common stock at exercise prices of $0.13 and $9.46 per share. This filing is procedural and complies with Section 16 reporting: it records change in beneficial ownership rather than a discretionary open-market purchase or sale. For governance review, the key facts are vesting status, exercise prices, and resulting direct ownership level of 93,281 shares.

Securities Analyst

TL;DR: Two option exercises added 47,890 shares to direct holdings; no derivative holdings reported after the transactions.

The Form 4 shows exercises on 09/05/2025 that resulted in acquisition entries in both the non-derivative and derivative tables: 37,890 units at $0.13 and 10,000 units at $9.46. The derivative table records the underlying common stock amounts and lists zero derivative securities beneficially owned following the transactions, consistent with conversion of options into shares. The filing does not disclose sales, pledges, or other dispositions, and is limited to these exercises and the post-transaction direct ownership total.

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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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^*

KANTOFF AARON

(Last) (First) (Middle)

C/O TOURMALINE BIO, INC.

27 WEST 24TH STREET, SUITE 702

(Street)

NEW YORK NY 10010

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Tourmaline Bio, Inc. [ TRML ]

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

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

3. Date of Earliest Transaction (Month/Day/Year)
09/05/2025

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	09/05/2025		M		37,890	A	$0.13	83,281	D
Common Stock	09/05/2025		M		10,000	A	$9.46	93,281	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
Stock Option (Right to Buy)	$0.13	09/05/2025		M			37,890	(1)	02/02/2033	Common Stock	37,890	$0	0	D
Stock Option (Right to Buy)	$9.46	09/05/2025		M			10,000	(1)	10/22/2033	Common Stock	10,000	$0	0	D

Explanation of Responses:

1. The shares subject to the option are fully vested and immediately exercisable.

	/s/ Brad Middlekauff, Attorney-in-Fact	09/09/2025
	** 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 did Aaron Kantoff (TRML) report on Form 4?

The Form 4 reports that Aaron Kantoff exercised options on 09/05/2025 acquiring 37,890 shares at $0.13 and 10,000 shares at $9.46, resulting in 93,281 shares beneficially owned.

What is the significance of transaction code M on this TRML Form 4?

The filing records transaction code M for both entries related to the 09/05/2025 option exercises as shown in the Form 4 tables.

Are the exercised options vested for the TRML reporting person?

Yes. The Form 4 includes an explanation stating the shares subject to the option are fully vested and immediately exercisable.

How many total shares were acquired in the reported transactions for TRML?

A total of 47,890 shares were acquired on 09/05/2025 (37,890 shares and 10,000 shares).

Who signed the Form 4 for the TRML reporting person?

The filing is signed by /s/ Brad Middlekauff, Attorney-in-Fact with the signature date 09/09/2025 as shown on the form.