Avidity Biosciences, Inc. — Director's Dealing 2025

Aug 8, 2025

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Avidity Biosciences, Inc. (RNA)
CIK: 0001599901
Period of Report: 2025-08-06

Reporting Person: Mosbrooker Eric (Chief Commercial Officer)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2025-08-06	Common Stock	M	124687	$9.05	Acquired	185807	Direct
2025-08-06	Common Stock	S	124687	$44.0626	Disposed	61120	Direct
2025-08-06	Common Stock	S	6120	$44.0626	Disposed	55000	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2025-08-06	Stock Option (Right to Buy)	$9.05	M	124687	Disposed	2033-12-31	Common Stock (124687)	Direct

Footnotes

F1: The sales reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan previously adopted by the Reporting Person on September 11, 2024.

F2: This represents a weighted-average price. These shares were sold in multiple transactions at prices ranging from $40.54 to $45.44. 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.

F3: 1/48th of the total number of shares subject to the option shall vest on each monthly anniversary of January 1, 2024 (the "Vesting Commencement Date"), subject to the Reporting Person's continuous service to the Issuer on each such vesting date, so that the options shall be fully vested on the fourth anniversary of the Vesting Commencement Date.