Tectonic Therapeutic withholds 1,545 CEO shares for taxes

Q: How many shares did Tectonic Therapeutic CEO Alise Reicin have withheld?

On September 25, 2026, the issuer withheld 1,545 common shares from CEO Alise Reicin at a reported $23.67 per share to satisfy tax-withholding obligations tied to vesting and settlement of restricted stock units granted September 25, 2025.

Q: How many TECX shares are held by Alise Reicin's family trust?

The Reicin-Boiarsky Family Trust held 127,030 common shares as of September 25, 2026. Reicin's spouse is a co-trustee, and Reicin may be deemed to share voting and dispositive power over the trust's securities; she disclaims beneficial ownership except to the extent of her pecuniary interest.

After the withholding, Alise Reicin reported direct holdings of 309,078 common shares; the Reicin-Boiarsky Family Trust held 127,030 shares.

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Rhea-AI Filing Summary

Tectonic Therapeutic, Inc. (TECX) reported that CEO Alise Reicin had 1,545 common shares withheld by the issuer on September 25, 2026, to satisfy tax-withholding obligations connected with vesting and settlement of restricted stock units granted on September 25, 2025. The reported price was $23.67 per share. After the transaction, her reported direct holdings were 309,078 common shares. As of September 25, 2026, the Reicin-Boiarsky Family Trust held 127,030 common shares.

Insider Trade Summary

Tax Withholding: 1,545 shares

Tax Withholding 2 txns

Insider REICIN ALISE

Role Chief Executive Officer

Type	Security	Shares	Price	Value
Tax Withholding	Common Stock ^F1	1,545	$23.67	$37K
holding	Common Stock ^F2	--	--	--

Holdings After Transaction: Common Stock — 309,078 shares (Direct); Common Stock — 127,030 shares (Indirect, By Trust)

Footnotes (2)

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.
F2. 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.

Key Figures

Shares withheld: 1,545 common shares Reported price per share: $23.67 per share Direct holdings after transaction: 309,078 common shares +1 more

4 metrics

Shares withheld 1,545 common shares September 25, 2026, to satisfy tax-withholding obligations

Reported price per share $23.67 per share September 25, 2026 transaction

Direct holdings after transaction 309,078 common shares Alise Reicin

Family trust holdings 127,030 common shares Reicin-Boiarsky Family Trust as of September 25, 2026

Key Terms

restricted stock units, tax withholding obligations, beneficial ownership, pecuniary interest

4 terms

restricted stock units financial

"vesting and settlement of the restricted stock units granted"

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.

tax withholding obligations financial

"to satisfy the Reporting Person's tax withholding obligations"

beneficial ownership regulatory

"disclaims beneficial ownership of the shares held by the Trust"

Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.

pecuniary interest financial

"except to the extent of her pecuniary interest therein"

FAQ

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

How many shares did Tectonic Therapeutic CEO Alise Reicin have withheld?

On September 25, 2026, the issuer withheld 1,545 common shares from CEO Alise Reicin at a reported $23.67 per share to satisfy tax-withholding obligations tied to vesting and settlement of restricted stock units granted September 25, 2025.

How many TECX shares are held by Alise Reicin's family trust?

The Reicin-Boiarsky Family Trust held 127,030 common shares as of September 25, 2026. Reicin's spouse is a co-trustee, and Reicin may be deemed to share voting and dispositive power over the trust's securities; she disclaims beneficial ownership except to the extent of her pecuniary interest.

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

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Available on EDGAR 10/02/2026 - 04:58 PM Accepted by SEC EDGAR 10/02/2026 - 04:57 PM

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).

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 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)

X	Director	10% Owner
X	Officer (give title below)	Other (specify below)
	Chief Executive 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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	09/25/2026		F		1,545⁽¹⁾	D	$23.67	309,078	D
Common Stock								127,030	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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)

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. 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	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)

Source: View Original Filing on SEC EDGAR