[Form 4] Avidity Biosciences, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Teresa McCarthy, Chief Human Resources Officer of Avidity Biosciences, reported option exercise and a contemporaneous sale on 09/15/2025. She exercised 15,000 stock options at an exercise price of $22.34, which increased her total reported beneficial ownership of common stock to 112,130 shares. On the same date she sold 15,000 shares for a weighted-average price of $41.4095, leaving 97,130 shares reported beneficially owned. The transactions were executed under a Rule 10b5-1 trading plan adopted 04/11/2025. The option shares are fully vested and the option grant shows 85,000 derivative shares remaining.

Positive

• Transactions executed under a Rule 10b5-1 plan (adopted 04/11/2025), indicating pre-planned, compliant insider trading
• Exercise price: Options exercised at $22.34, while shares were sold at a higher weighted-average price of $41.4095, realizing gains
• Options fully vested as of the exercise date, confirming immediate exercisability

Negative

• Sale of 15,000 shares reduced reported beneficial ownership from 112,130 to 97,130, reflecting insider liquidity
• Weighted-average sale price spans a range ($40.02 to $44.47), indicating the sale occurred in multiple transactions rather than a single price point

Insights

Financial Analyst

TL;DR: Insider exercised options and sold an equal number of shares via a pre-established 10b5-1 plan; routine liquidity event, neutral signal.

The filing shows a simultaneous exercise of 15,000 options at $22.34 and sale of 15,000 shares at a weighted-average $41.4095, executed under a Rule 10b5-1 plan adopted 04/11/2025. This is a common pattern for insiders to capture gains and diversify personal holdings while complying with insider-trading protocols. The filing confirms the options were fully vested and that 85,000 option-based shares remain outstanding to the reporting person.

Corporate Governance Expert

TL;DR: Use of a documented 10b5-1 plan and attorney-in-fact signature indicates procedural compliance and pre-planned timing.

The disclosure includes the plan adoption date (04/11/2025) and an attorney-in-fact signature on 09/17/2025, reflecting formal execution and reporting. The simultaneous exercise and sale were processed under the plan, reducing potential concerns about opportunistic insider trading. Reporting shows clear quantities, prices, and that the options were fully exercisable, which supports transparency for shareholders and regulators.

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).

1. Name and Address of Reporting Person^*

McCarthy Teresa

(Last) (First) (Middle)

C/O AVIDITY BIOSCIENCES, INC.

3020 CALLAN RD.

(Street)

SAN DIEGO CA 92121

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Avidity Biosciences, Inc. [ RNA ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

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

3. Date of Earliest Transaction (Month/Day/Year)
09/15/2025

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	09/15/2025		M(1)		15,000	A	$22.34	112,130	D
Common Stock	09/15/2025		S(1)		15,000	D	$41.4095(2)	97,130	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
Stock Option (Right to Buy)	$22.34	09/15/2025		M(1)			15,000	(3)	02/01/2031	Common Stock	15,000	$0	85,000	D

Explanation of Responses:

1. The exercise and sales reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan previously adopted by the Reporting Person on April 11, 2025.

2. This represents a weighted-average price. These shares were sold in multiple transactions at prices ranging from $40.02 to $44.47. The Reporting Person undertakes to provide the Issuer, any securityholder of the Issuer, or the Staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

3. The shares subject to this option award are fully vested and exercisable as of the date hereof.

Remarks:

	/s/ John B. Moriarty, Jr., J.D., Attorney-in-Fact	09/17/2025
	** 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 did Avidity Biosciences (RNA) insider Teresa McCarthy do on 09/15/2025?

She exercised 15,000 stock options at an exercise price of $22.34 and sold 15,000 shares for a weighted-average price of $41.4095.

Were these transactions pre-planned under a trading plan?

Yes. The Form 4 states the transactions were effected pursuant to a Rule 10b5-1 trading plan adopted on 04/11/2025.

How many shares does Teresa McCarthy beneficially own after the transactions?

The filing reports 97,130 shares of common stock beneficially owned following the reported sale.

Are the exercised options fully vested?

Yes. The Form 4 states the 15,000 option shares subject to the award are fully vested and exercisable as of the transaction date.

What is the remaining number of option-based shares reported after the transaction?

The filing shows 85,000 derivative securities (stock options) beneficially owned following the reported transactions.