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

Rhea-AI Filing Summary

Tourmaline Bio (TRML) director reported insider transactions tied to the Novartis acquisition. On October 28, 2025, shares were disposed pursuant to the Merger Agreement after Merger Sub completed a cash tender offer at $48.00 per share.

The filing shows disposition of 515,997 shares held directly and 431,939 shares held indirectly through KVP Capital, LP. In addition, stock options were canceled for cash per the agreement: 10,000 options at a $9.46 exercise price, 10,000 options at $13.91, and 16,800 options at $18.73. Each option converted into cash equal to $48.00 minus its exercise price, multiplied by the number of underlying shares, subject to tax withholding.

Insights

M&A and Securities Reporting Analyst

Insider Form 4 confirms tender at $48 and option cash-out mechanics.

The report documents a director’s tendered common shares and automatic option cancellations executed under the Merger Agreement with Novartis. The common shares were exchanged at $48.00 per share following completion of the tender offer on October 28, 2025.

Option awards were converted to cash based on the disclosed formula: the difference between $48.00 and each option’s exercise price, times the underlying shares. This is a standard cash-out treatment at deal close.

As a Form 4, this is administrative confirmation of closing mechanics rather than a new capital event. Market impact depends on previously announced merger terms, with no new financial guidance provided here.

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

X

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^*

Castelein Caley

(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)
10/28/2025

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	10/28/2025		U(1)		515,997	D	(2)	0	D
Common Stock	10/28/2025		U(1)		431,939	D	(2)	0	I	By KVP Capital, LP(3)

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
Employee Stock Option (Right to Buy)	$9.46	10/28/2025		D(1)			10,000	(4)	(4)	Common Stock	10,000	(4)	0	D
Employee Stock Option (Right to Buy)	$13.91	10/28/2025		D(1)			10,000	(4)	(4)	Common Stock	10,000	(4)	0	D
Employee Stock Option (Right to Buy)	$18.73	10/28/2025		D(1)			16,800	(4)	(4)	Common Stock	16,800	(4)	0	D

Explanation of Responses:

1. This Form 4 reports securities disposed pursuant to that certain Agreement and Plan of Merger (the "Merger Agreement"), dated as of September 8, 2025, by and among Issuer, Novartis AG, a company limited by shares (Aktiengesellschaft) incorporated under the laws of Switzerland ("Parent"), and Torino Merger Sub Inc., a Delaware corporation and indirect wholly owned subsidiary of Parent ("Merger Sub"). Pursuant to the Merger Agreement, on October 28, 2025, Merger Sub completed a cash tender offer to acquire all of the shares of common stock of the Issuer, par value $0.0001 (the "Shares"), issued and outstanding immediately prior to the effective time of the merger (the "Effective Time"), in exchange for $48.00 in cash per Share, subject to any applicable withholding of taxes (the "Merger Consideration").

2. Pursuant to the terms of the Merger Agreement, each Share was tendered in exchange for $48.00 in cash per Share.

3. These shares are held by KVP. The Reporting Person is the Managing Member of KVP Capital GP, LLC, the General Partner of KVP and, as such, has sole voting and investment power with respect to the shares held by KVP. The Reporting Person disclaims beneficial ownership of the shares held by KVP except to the extent of his pecuniary interest therein and this report is not an admission that the Reporting Person is the beneficial owner of these securities for purposes of Section 16 or for any other purpose.

4. Pursuant to the terms of the Merger Agreement, each stock option that was outstanding and unexercised immediately prior to the Effective Time was automatically canceled and terminated and converted into the right to receive an amount in cash, without interest, equal to the product of (i) the amount by which the Merger Consideration exceeds the applicable exercise price per Share of such option and (ii) the aggregate number of Shares issuable upon exercise of such option or portion thereof, subject to any applicable withholding of taxes.

	/s/ Brad Middlekauff, Attorney-in-Fact	10/28/2025
	** 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 TRML’s Form 4 report regarding the Novartis deal?

It reported the director’s disposition of common shares and the cash-out of stock options pursuant to the Merger Agreement at $48.00 per share.

How many TRML shares did the director dispose of directly and indirectly?

The filing lists 515,997 shares held directly and 431,939 shares held indirectly through KVP Capital, LP.

What was the cash consideration per TRML share?

Each tendered share was exchanged for $48.00 in cash, subject to tax withholding.

How were TRML stock options treated in the transaction?

Options were canceled and converted to cash equal to $48.00 minus the exercise price, multiplied by the underlying shares.

Which specific TRML option grants were canceled?

Grants of 10,000 options at $9.46, 10,000 at $13.91, and 16,800 at $18.73 were canceled for cash.

When did the TRML tender offer complete?

The tender offer completed on October 28, 2025.