Tectonic ex-director plans $383.7K share sale

Tectonic Therapeutic, Inc. (TECX) is the subject of a notice under Rule 144 filed for the account of former director Terrance McGuire.

Rhea-AI Filing Summary

Tectonic Therapeutic, Inc. (TECX) is the subject of a notice under Rule 144 filed for the account of former director Terrance McGuire. The notice states an intention to sell 10,200 shares of common stock, to be acquired through a stock option exercise for cash and sold through Morgan Stanley Smith Barney LLC, with an indicated aggregate market value of $383,670.96. The filing lists 19,549,366 shares of common stock outstanding and a proposed sale date of 08/21/2026 on NASDAQ.

Key Figures

Shares to be sold: 10,200 shares Aggregate market value: $383,670.96 Shares outstanding: 19,549,366 shares +2 more

5 metrics

Shares to be sold 10,200 shares Common stock covered by the Rule 144 notice for proposed sale

Aggregate market value $383,670.96 Value associated with the 10,200 common shares in the Rule 144 notice

Shares outstanding 19,549,366 shares Common shares outstanding of Tectonic Therapeutic, Inc. listed in the notice

Proposed sale date 08/21/2026 Date listed for proposed sale of the common shares on NASDAQ

Securities holder status Former Director Status of Terrance McGuire in relation to Tectonic Therapeutic, Inc.

Key Terms

Rule 144, Stock Option Exercise, Former Director, Aggregate market value

4 terms

Rule 144 regulatory

"See the definition of "person" in paragraph (a) of Rule 144."

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

Stock Option Exercise financial

"Common | 08/21/2026 | Stock Option Exercise | Issuer"

A stock option exercise is the act of using a previously granted right to buy shares of a company's stock at a specific, predetermined price by paying that price and receiving the shares. It matters to investors because exercising changes who owns the shares (which can dilute existing ownership), can trigger taxable events and shift potential gains or losses, and affects voting power and the company’s outstanding share count—like turning a voucher into an actual product that becomes part of circulating supply.

Former Director financial

"Former Director 144: Securities Information"

Aggregate market value financial

"Common ... | 10200 | 383670.96 | 19549366 | 08/21/2026"

Aggregate market value is the combined price you would pay to buy all outstanding shares of a company or all companies in a group at current market prices — essentially the sum of each stock’s market capitalization. It matters to investors because it shows the overall size and weight of an investment or sector (like the total cost to buy every piece of a puzzle), helps compare scale across companies or markets, and influences index composition and risk exposure.

FAQ

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

What does the Form 144 filing disclose for Tectonic Therapeutic, Inc. (TECX)?

The filing discloses that former director Terrance McGuire has given notice under Rule 144 of a proposed sale of 10,200 shares of Tectonic Therapeutic, Inc. common stock, to be sold through Morgan Stanley Smith Barney LLC on or after 08/21/2026.

How many Tectonic Therapeutic (TECX) shares are covered by this Form 144?

The notice covers a proposed sale of 10,200 shares of Tectonic Therapeutic, Inc. common stock. The filing also lists 19,549,366 shares of common stock outstanding, which is a separate context figure, not the amount proposed for sale.

What is the indicated market value of the TECX shares in this Form 144?

The Form 144 lists an aggregate market value of $383,670.96 for the 10,200 common shares of Tectonic Therapeutic, Inc. covered by the notice. This amount reflects the value associated with the proposed sale under Rule 144.

How will the Tectonic Therapeutic (TECX) shares be obtained for this Rule 144 sale?

The filing states that the 10,200 shares to be sold will come from a stock option exercise for cash from the issuer. After exercise, the resulting common shares are expected to be sold through the designated broker.

When is the proposed sale date for the TECX shares in this Form 144?

The Form 144 lists a proposed sale date of 08/21/2026 for the 10,200 shares of Tectonic Therapeutic, Inc. common stock, with the shares to be sold on NASDAQ through Morgan Stanley Smith Barney LLC.

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

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Available on EDGAR 08/21/2026 - 05:58 PM EDT Accepted by SEC EDGAR 08/21/2026 - 05:58 PM EDT Learn about SEC filing dates

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0001117003
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	TECTONIC THERAPEUTIC, INC.
SEC File Number	001-38537
Address of Issuer	490 ARSENAL WAY SUITE 200 WATERTOWN MASSACHUSETTS 02472
Phone	(339) 666-3320
Name of Person for Whose Account the Securities are To Be Sold	TERRANCE MCGUIRE
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Former Director

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common	Morgan Stanley Smith Barney LLC Executive Financial Services 1 New York Plaza 8th Floor New York NY 10004	10200	383670.96	19549366	08/21/2026	NASDAQ

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common	08/21/2026	Stock Option Exercise	Issuer			10200	08/21/2026	Cash

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Nothing to Report

144: Remarks and Signature

Remarks
Date of Notice	08/21/2026
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	/s/ TERRANCE GERARD MCGUIRE
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)