Tectonic Therapeutic (TECX) CSO sells shares after exercising options

Rhea-AI Filing Summary

Tectonic Therapeutic, Inc. Chief Scientific Officer Peter McNamara reported option exercises and share sales on March 6, 2026. He exercised employee stock options for 2,500 and 215 shares, which converted into common stock at exercise prices of $2.3800 and $14.7100 per share.

On the same date, he sold 6,047 shares of common stock at $30.0000 per share and 215 shares at $35.0000 per share in open‑market transactions. After these trades, he directly owned 55,285 shares of Tectonic Therapeutic common stock. The filing notes these exercises and sales were made under a Rule 10b5‑1 trading plan adopted on November 14, 2025.

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

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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^*

McNamara Peter

(Last) (First) (Middle)

C/O TECTONIC THERAPEUTIC, INC.

490 ARSENAL WAY, SUITE 200

(Street)

WATERTOWN MA 02472

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Tectonic Therapeutic, Inc. [ TECX ]

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

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

3. Date of Earliest Transaction (Month/Day/Year)
03/06/2026

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	03/06/2026		M(1)		2,500	A	$2.38	61,332	D
Common Stock	03/06/2026		M(1)		215	A	$14.71	61,547	D
Common Stock	03/06/2026		S(1)		6,047	D	$30	55,500	D
Common Stock	03/06/2026		S(1)		215	D	$35	55,285	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
Employee Stock Option (Right to Buy)	$2.38	03/06/2026		M(1)			2,500	(2)	06/27/2031	Common Stock	2,500	(3)	31,959	D
Employee Stock Option (Right to Buy)	$14.71	03/06/2026		M(1)			215	(4)	09/24/2035	Common Stock	215	$0	8,045	D

Explanation of Responses:

1. These exercises and sales were made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 14, 2025.

2. 25% of the shares subject to the option vested on June 1, 2022; and the remainder of the shares subject to the option vest in 36 equal monthly installments with the final amount vesting on June 1, 2025, subject to the Reporting Person's continued service to the Issuer on each such vesting date.

3. Received in exchange for a stock option to acquire 71,029 shares of common stock pursuant to that certain merger, as more fully described on the Reporting Person's Form 4 filed with the Securities and Exchange Commission on June 24, 2024. https://www.sec.gov/Archives/edgar/data/1681087/000141588924017962/xslF345X05/form4-06242024_080611.xml

4. The shares subject to the option vest in 48 equal monthly installments beginning on October 25, 2025, subject to the Reporting Person's continued service to the Issuer on each such vesting date.

	/s/ Daniel Lochner, Attorney-in-Fact	03/09/2026
	** 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).
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FAQ

What did Tectonic Therapeutic (TECX) insider Peter McNamara report on this Form 4?

Peter McNamara reported option exercises and related stock sales. He exercised employee stock options into common shares, then sold 6,047 shares at $30.0000 and 215 shares at $35.0000 on March 6, 2026, under a pre‑established Rule 10b5‑1 trading plan.

How many Tectonic Therapeutic (TECX) shares did the CSO sell and at what prices?

He sold 6,047 shares of common stock at $30.0000 per share and 215 shares at $35.0000 per share. Both transactions occurred on March 6, 2026, and were reported as open‑market or private sales on his Form 4 filing.

How many Tectonic Therapeutic (TECX) options did Peter McNamara exercise?

He exercised employee stock options covering 2,500 shares and 215 shares. These derivative securities converted into common stock at exercise prices of $2.3800 and $14.7100 per share, respectively, as disclosed in the Form 4 transaction details for March 6, 2026.

What is Peter McNamara’s Tectonic Therapeutic (TECX) share ownership after these transactions?

After completing the reported exercises and sales, Peter McNamara directly owned 55,285 shares of Tectonic Therapeutic common stock. This post‑transaction holding figure is taken from the Form 4’s "shares following transaction" column for his non‑derivative common stock position.

Were Tectonic Therapeutic (TECX) CSO trades made under a 10b5-1 plan?

Yes. A footnote states the option exercises and stock sales were executed under a Rule 10b5‑1 trading plan. The plan was adopted by the reporting person on November 14, 2025, providing for pre‑arranged trading independent of day‑to‑day market decisions.

What role does Peter McNamara hold at Tectonic Therapeutic (TECX)?

Peter McNamara is identified as the Chief Scientific Officer of Tectonic Therapeutic, Inc. This officer title is disclosed in the Form 4 reporting his March 6, 2026 option exercises and subsequent common stock sales, all held as direct ownership after the transactions.