Tectonic Therapeutic (TECX) CMO sells 1,065 shares in 10b5-1 trade

Q: Was the TECX insider sale by the CMO under a Rule 10b5-1 plan?

Yes. The sale of 1,065 shares by Chief Medical Officer Marcella K. Ruddy was made pursuant to a Rule 10b5-1 trading plan . The footnote states this plan was adopted on April 8, 2025 , indicating the trade was pre-arranged.

Q: What type of transaction was reported in the TECX Form 4 filing?

The Form 4 reports an open-market sale of Common Stock, coded “S” for Sale in open market or private transaction . Chief Medical Officer Marcella K. Ruddy sold 1,065 shares at $30.00 per share and retained 67,682 shares afterward.

Q: Does the Tectonic Therapeutic (TECX) Form 4 show any option exercises?

No. The insider data shows no derivative transactions and no option exercises . The filing only reports a single non-derivative transaction: an open-market sale of 1,065 Common Stock shares at $30.00 per share by the Chief Medical Officer.

Filing Impact

(Neutral)

Filing Sentiment

(Negative)

Form Type

Rhea-AI Filing Summary

Tectonic Therapeutic, Inc. Chief Medical Officer Marcella K. Ruddy reported an open-market sale of 1,065 shares of Common Stock at $30.00 per share on May 4, 2026. Following this transaction, she directly holds 67,682 shares of the company’s Common Stock. The sale was executed under a Rule 10b5-1 trading plan adopted on April 8, 2025, indicating it was pre-arranged rather than a discretionary trade.

Insider Trade Summary 10b5-1

Net Seller: 1,065 shares ($31,950)

Net Sell 1 txn

Insider Ruddy Marcella K.

Role Chief Medical Officer

Sold 1,065 shs ($32K)

Type	Security	Shares	Price	Value
Sale	Common Stock	1,065	$30.00	$32K

Holdings After Transaction: Common Stock — 67,682 shares (Direct, null)

Footnotes (1)

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Key Figures

Shares sold: 1,065 shares Sale price per share: $30.00 per share Shares held after transaction: 67,682 shares +2 more

5 metrics

Shares sold 1,065 shares Open-market sale of Common Stock on May 4, 2026

Sale price per share $30.00 per share Price for the 1,065 Common Stock shares sold

Shares held after transaction 67,682 shares Direct holdings of CMO Marcella K. Ruddy after the sale

Transaction type code Code S Sale in open market or private transaction

10b5-1 plan adoption date April 8, 2025 Date the Rule 10b5-1 trading plan was adopted

Key Terms

Rule 10b5-1 trading plan, open-market sale, Common Stock, Form 4

4 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" for the 1,065 Common Stock shares"

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" for the 1,065-share transaction"

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 regulatory

"The insider activity was disclosed in a Form 4 insider trading report"

Form 4 is a official document that company insiders, such as executives or major shareholders, file with regulators whenever they buy or sell company shares. It provides transparency about how those with inside knowledge are trading, helping investors see if insiders are confident in the company's prospects or may be selling for personal reasons. This information can influence investor decisions by revealing insiders' perspectives on the company's value.

Form 4 Insider Transactions: What Each Field Means →

05/06/2026 - 05:00 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^*

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)
05/04/2026

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	05/04/2026		S⁽¹⁾		1,065	D	$30	67,682	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)
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 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	05/06/2026
	** 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

FAQ

What insider transaction did TECX’s Chief Medical Officer report?

Tectonic Therapeutic’s Chief Medical Officer, Marcella K. Ruddy, reported selling 1,065 shares of Common Stock at $30.00 per share. The transaction was an open-market sale and was disclosed on a Form 4 insider trading report.

How many Tectonic Therapeutic (TECX) shares does the CMO hold after the sale?

After the reported sale, Chief Medical Officer Marcella K. Ruddy directly holds 67,682 shares of Tectonic Therapeutic Common Stock. This figure reflects her position immediately following the 1,065-share open-market sale at $30.00 per share.

Was the TECX insider sale by the CMO under a Rule 10b5-1 plan?

Yes. The sale of 1,065 shares by Chief Medical Officer Marcella K. Ruddy was made pursuant to a Rule 10b5-1 trading plan. The footnote states this plan was adopted on April 8, 2025, indicating the trade was pre-arranged.

What type of transaction was reported in the TECX Form 4 filing?

The Form 4 reports an open-market sale of Common Stock, coded “S” for Sale in open market or private transaction. Chief Medical Officer Marcella K. Ruddy sold 1,065 shares at $30.00 per share and retained 67,682 shares afterward.

Does the Tectonic Therapeutic (TECX) Form 4 show any option exercises?

No. The insider data shows no derivative transactions and no option exercises. The filing only reports a single non-derivative transaction: an open-market sale of 1,065 Common Stock shares at $30.00 per share by the Chief Medical Officer.