Tectonic Therapeutic (TECX) CMO sells 1,000 shares in planned trade

Rhea-AI Filing Summary

Tectonic Therapeutic, Inc. Chief Medical Officer Marcella K. Ruddy executed an open-market sale of 1,000 shares of Common Stock at $31.05 per share on April 1, 2026. She held 68,747 shares afterward, and the sale was made under a pre-established Rule 10b5-1 trading plan.

Insider Trade Summary 10b5-1

Net Seller: 1,000 shares ($31,050)

Net Sell 1 txn

Insider Ruddy Marcella K.

Role Chief Medical Officer

Sold 1,000 shs ($31K)

Type	Security	Shares	Price	Value
Sale	Common Stock	1,000	$31.05	$31K

Holdings After Transaction: Common Stock — 68,747 shares (Direct)

Footnotes (1)

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Key Figures

Shares sold: 1,000 shares Sale price per share: $31.05 per share Shares owned after transaction: 68,747 shares +1 more

4 metrics

Shares sold 1,000 shares Open-market sale on April 1, 2026

Sale price per share $31.05 per share Common Stock sale on April 1, 2026

Shares owned after transaction 68,747 shares Direct ownership following sale

Net shares sold 1,000 shares Net-sell direction from transaction summary

Key Terms

Rule 10b5-1 trading plan, open-market sale, Common Stock

3 terms

Rule 10b5-1 trading plan regulatory

"This sale was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person"

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.

open-market sale financial

"transaction_action: open-market sale"

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

Common Stock financial

"security_title: Common Stock"

Common stock represents ownership shares in a company, giving investors a stake in its success and a say in important decisions through voting rights. It is the most common type of stock traded on markets and can provide income through dividends, as well as potential for value growth. For investors, holding common stock means sharing in the company’s profits and risks.

Form 4 Insider Transactions: What Each Field Means →

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^*

Ruddy Marcella K.

(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 Medical Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
04/01/2026

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	04/01/2026		S(1)		1,000	D	$31.05	68,747	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 sale was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on April 8, 2025.

	/s/ Daniel Lochner, Attorney-in-Fact	04/03/2026
	** 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)

FAQ

What did Tectonic Therapeutic (TECX) insider Marcella K. Ruddy do in this Form 4?

Marcella K. Ruddy, Chief Medical Officer of Tectonic Therapeutic, reported an open-market sale of 1,000 shares of Common Stock at $31.05 per share. The transaction was executed on April 1, 2026, and she retained 68,747 shares following the sale.

How many TECX shares does Marcella K. Ruddy hold after this reported sale?

After the reported transaction, Marcella K. Ruddy beneficially owned 68,747 shares of Tectonic Therapeutic Common Stock. This figure reflects her direct holdings immediately following the open-market sale of 1,000 shares disclosed in the Form 4 filing for April 1, 2026.

At what price did the Tectonic Therapeutic (TECX) insider shares sell in this Form 4?

The Form 4 reports that 1,000 shares of Tectonic Therapeutic Common Stock were sold at $31.05 per share. This was an open-market transaction, and the disclosed price represents the sale price per share on April 1, 2026.

Was the TECX insider sale by Marcella K. Ruddy made under a Rule 10b5-1 plan?

Yes. A footnote explains the sale was made pursuant to a Rule 10b5-1 trading plan adopted by Marcella K. Ruddy on April 8, 2025. Such pre-arranged plans automate trades, reducing the significance of timing decisions for this transaction.