RNA insider files Form 144 for 19,688 shares after option exercise; prior 130,807-share 10b5-1 sale

Rhea-AI Filing Summary

Avidity Biosciences (RNA) filing a Form 144 shows a proposed sale of 19,688 common shares with an aggregate market value of $929,864.24 to be executed on 09/03/2025 through Morgan Stanley Smith Barney on NASDAQ. The filing indicates these shares were acquired the same day by exercise of stock options and paid in cash. The notice also discloses prior Rule 10b5-1 sales by the same person on 08/06/2025 totaling 130,807 shares for $5,763,699.79. Several standard filer and issuer identification fields in the form are blank or not provided in the text.

Positive

• Transaction transparency: Filing discloses class, share count, acquisition method, broker, sale date, and aggregate value
• Compliance detail: Prior 10b5-1 sales and exercise details are reported, supporting regulatory disclosure requirements

Negative

• Insider selling activity: Proposed sale and prior 10b5-1 sales indicate notable insider liquidity that may be viewed negatively by some investors
• Missing identification fields: Several filer and issuer identifier fields are blank in the provided content, reducing clarity for verification

Insights

Securities Analyst

TL;DR: Insider exercised options and plans a cash sale of 19,688 shares; prior 10b5-1 sales earlier in August were substantially larger.

The filing documents a routine insider liquidity event where shares were acquired by option exercise and are proposed for immediate sale. The August 6, 2025 10b5-1 sales of 130,807 shares for about $5.76M indicate prior asset monetization. These disclosures are procedural under Rule 144 and 10b5-1; they reveal insider selling activity but not company operational performance. Given the lack of additional issuer context or material corporate events in this filing, the investor impact is limited to signaling insider liquidity rather than new material company news.

Corporate Governance Expert

TL;DR: Filing appears compliant with Rule 144; missing issuer/filer identifiers reduce clarity for investors.

The notice meets disclosure requirements by stating class, amount, acquisition method, and planned broker execution. However, several issuer and filer identification fields are blank in the provided content, which limits traceability and investor verification. The combination of an immediate exercise-and-sale and prior 10b5-1 transactions suggests planned liquidity rather than opportunistic trades. From a governance perspective, ensure the trading plan and any blackout/insider windows are referenced elsewhere to confirm compliance with internal policies.

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK
Filer CCC
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer

SEC File Number

Address of Issuer

Phone

Name of Person for Whose Account the Securities are To Be Sold

See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.

Relationship to Issuer

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common	Morgan Stanley Smith Barney LLC Executive Financial Services 1 New York Plaza 8th Floor New York NY 10004	19688	929864.24	128653337	09/03/2025	NASDAQ

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common	09/03/2025	Exercise of Stock Options	Issuer			19688	09/03/2025	Cash

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
10b5-1 Sales for ERIC MOSBROOKER 10578 Science Center Drive, Suite 125 San Diego CA 92121	Common	08/06/2025	130807	5763699.79

144: Remarks and Signature

Remarks

Date of Notice

Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1

ATTENTION:

The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.

Signature

ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)

FAQ

What does the Form 144 filed for Avidity Biosciences (RNA) disclose?

The filing discloses a proposed sale of 19,688 common shares valued at $929,864.24 to be sold on 09/03/2025 via Morgan Stanley on NASDAQ; shares were acquired the same day by exercise of stock options and paid in cash.

Were there any prior insider sales disclosed for RNA?

Yes. The filing shows 10b5-1 sales on 08/06/2025 of 130,807 shares generating $5,763,699.79 in gross proceeds.

How were the 19,688 shares acquired according to the filing?

The shares were acquired on 09/03/2025 by exercise of stock options from the issuer and were paid for in cash on the same date.

Which broker is handling the proposed sale for RNA?

Morgan Stanley Smith Barney LLC Executive Financial Services (1 New York Plaza, 8th Floor, New York, NY) is named as the broker.

Does this Form 144 indicate any material undisclosed company information?

No. The filer represents they are not aware of any undisclosed material adverse information; the form contains no additional company operational or financial disclosures.