Tectonic Therapeutic: McNamara sells 536 shares

The Chief Scientific Officer's sale was made under a Rule 10b5-1 plan adopted November 14, 2025, alongside a separate tax-withholding transaction.

Rhea-AI Filing Summary

Tectonic Therapeutic, Inc. (TECX) Chief Scientific Officer Peter McNamara reported selling 536 shares on September 30, 2026, at a weighted average price of $23.04 per share; the shares sold in transactions ranging from $22.61 to $23.32. The sale was made under a Rule 10b5-1 trading plan adopted November 14, 2025. On September 25, 2026, the issuer withheld 444 shares to satisfy his tax withholding obligations from vesting and settlement of restricted stock units granted September 25, 2025; the reported transaction price was $23.67 per share.

Insider Trade Summary 10b5-1

Net Seller: 536 shares

Net Sell 2 txns

Insider McNamara Peter

Role Chief Scientific Officer

Sold 536 shs ($12K)

Type	Security	Shares	Price	Value
Sale	Common Stock F2, F3	536	$23.04	$12K
Tax Withholding	Common Stock F1	444	$23.67	$11K

Holdings After Transaction: Common Stock — 54,305 shares (Direct)

Footnotes (3)

1. F1. This transaction reported represents the withholding of shares by the Issuer to satisfy the Reporting Person's tax withholding obligations in connection with the vesting and settlement of the restricted stock units granted on September 25, 2025.
2. F2. This sale was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 14, 2025.
3. F3. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $22.61 to $23.32, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder 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.

Key Figures

Shares sold: 536 shares Weighted average sale price: $23.04 per share Sale price range: $22.61 to $23.32 per share +2 more

5 metrics

Shares sold 536 shares September 30, 2026

Weighted average sale price $23.04 per share Sale on September 30, 2026

Sale price range $22.61 to $23.32 per share Multiple sale transactions

Shares withheld for taxes 444 shares September 25, 2026

Reported price per share $23.67 per share Tax-withholding transaction on September 25, 2026

Key Terms

Rule 10b5-1 trading plan, weighted average price, restricted stock units

3 terms

Rule 10b5-1 trading plan regulatory

"sale was made pursuant to a Rule 10b5-1 trading plan"

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

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.

restricted stock units financial

"vesting and settlement of the restricted stock units"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

How many TECX shares did Chief Scientific Officer Peter McNamara sell?

Peter McNamara sold 536 shares on September 30, 2026, at a weighted average price of $23.04 per share. The shares were sold in multiple transactions at prices ranging from $22.61 to $23.32, under a Rule 10b5-1 plan adopted November 14, 2025.

How many TECX shares were withheld for Peter McNamara's taxes?

The issuer withheld 444 shares on September 25, 2026, to satisfy Peter McNamara's tax withholding obligations in connection with vesting and settlement of restricted stock units granted September 25, 2025. The reported transaction price was $23.67 per share.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 10/02/2026 - 05:01 PM Accepted by SEC EDGAR 10/02/2026 - 05:00 PM Learn about SEC filing dates

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

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 MASSACHUSETTS 02472

(City) (State) (Zip)

UNITED STATES

(Country)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
09/25/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form 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)
			Code	V	Amount	(A) or (D)	Price
Common Stock	09/25/2026		F		444(1)	D	$23.67	54,841	D
Common Stock	09/30/2026		S(2)		536	D	$23.04(3)	54,305	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

Explanation of Responses:

1. This transaction reported represents the withholding of shares by the Issuer to satisfy the Reporting Person's tax withholding obligations in connection with the vesting and settlement of the restricted stock units granted on September 25, 2025.

2. This sale was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 14, 2025.

3. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $22.61 to $23.32, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder 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.

	/s/ Daniel Lochner, Attorney-in-Fact	10/02/2026
	** 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).
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)