[Form 4] Tectonic Therapeutic, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Tectonic Therapeutic, Inc. (TECX) – Form 4 filing overview

CEO and Director Alise Reicin reported a single administrative transaction dated 06/20/2025. The filing shows 859 common shares disposed (Code F) at a price of $19.81 per share. The shares were withheld by the issuer exclusively to cover tax obligations triggered by the vesting and settlement of restricted stock units granted on 12/04/2024. No open-market purchase or sale occurred.

After the transaction, Reicin’s beneficial ownership stands at 213,485 shares held directly and 124,530 shares held indirectly through the Reicin-Boiarsky Family Trust, where her spouse is co-trustee. No derivative securities were exercised, acquired, or disposed of, and there are no new option grants or expirations disclosed.

The reported disposal represents less than 0.3% of Reicin’s total reported holdings, indicating a routine, non-material adjustment rather than a directional change in insider sentiment.

Insights

Financial Analyst

TL;DR: Routine tax-withholding; negligible share impact, neutral signal.

The Form 4 shows Reicin surrendered 859 shares to settle taxes on RSU vesting—an expected, non-discretionary action coded “F.” Her post-transaction stake remains large (≈338k shares combined), so the dilution is immaterial. No open-market activity or derivative movements are reported, leaving the filing strategically neutral for investors. Such housekeeping transactions rarely influence valuation or sentiment.

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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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^*

REICIN ALISE

(Last) (First) (Middle)

C/O TECTONIC THERAPEUTIC, INC.

490 ARSENAL WAY, SUITE 210

(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)

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

3. Date of Earliest Transaction (Month/Day/Year)
06/20/2025

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	06/20/2025		F		859(1)	D	$19.81	213,485	D
Common Stock								124,530	I	By Trust(2)

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. The transaction reported represents the withholding of shares by the Issuer to satisfy the Reporting Person's tax withholding obligations in connection with the non-reportable vesting and settlement of restricted stock units granted on December 4, 2024.

2. These shares are held by the Reicin-Boiarsky Family Trust (the "Trust"). The Reporting Person's spouse is a co-trustee of the Trust. Accordingly, the Reporting Person may be deemed to have shared voting and dispositive power over the securities held by the Trust. The Reporting Person disclaims beneficial ownership of the shares held by the Trust except to the extent of her pecuniary interest therein, and this report shall not be deemed an admission that the Reporting Person is the beneficial owner of these securities for purposes of Section 16 or for any other purpose.

	/s/ Daniel Lochner, Attorney-in-Fact	06/24/2025
	** 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 insider activity did Tectonic Therapeutic (TECX) report on 06/20/2025?

CEO Alise Reicin disposed of 859 shares via issuer withholding to cover taxes on vested RSUs.

Was the TECX insider transaction an open-market sale?

No. The shares were withheld by the issuer (Code F) solely for tax obligations; no open-market trade occurred.

How many TECX shares does the CEO own after the Form 4 filing?

Reicin now holds 213,485 shares directly and 124,530 shares indirectly through a family trust.

Did the Form 4 disclose any new derivative securities for TECX?

No. The filing reports no acquisitions or disposals of options, warrants, or other derivatives.

Is the reported 859-share disposal material to TECX investors?

The disposal represents less than 0.3% of Reicin’s total holdings and is generally viewed as immaterial.