Sec Form 4 Filing - Lin Shao-Lee @ ACELYRIN, Inc. - 2023-10-04

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Lin Shao-Lee 2. Issuer Name and Ticker or Trading Symbol ACELYRIN, Inc. [ SLRN] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Chief Executive Officer (Last) (First) (Middle) C/O ACELYRIN, INC., 4149 LIBERTY CANYON RD. 3. Date of Earliest Transaction (MM/DD/YY) 10/04/2023 (Street) AGOURA HILLS, CA91301 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 10/04/2023 J( 1 ) 1,161,747 D $ 0 0 I See footnote ( 2 ) Common Stock 10/04/2023 J( 1 ) 132,236 A $ 0 487,205 I See footnote ( 3 ) Common Stock 1,612,434 D Common Stock 677,813 I See footnote ( 4 ) Common Stock 354,969 I See footnote ( 5 ) Common Stock 349,898 I See footnote ( 6 ) Common Stock 5,070 I See footnote ( 7 )

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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 of Derivative Security: 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

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Lin Shao-Lee C/O ACELYRIN, INC. 4149 LIBERTY CANYON RD. AGOURA HILLS, CA91301 X Chief Executive Officer Signatures /s/ Mina Kim, Attorney-in-fact 10/06/2023 Signature of Reporting Person Date

Explanation of Responses:

( 1 )As part of its dissolution, Woodland Hills Partner LLC (the "LLC"), distributed its 1,161,747 shares of common stock to its limited partners. As part of that distribution, 132,236 shares were distributed to the Shao-Lee Lin 2020 Gift Trust Dtd 7/16/20. This distribution arises from the purchase of preferred stock by the Reporting Person as a limited partner in the LLC on the same pricing terms as the other participating investors in each round of financing. The remaining 1,029,511 shares were distributed to other LLC limited partners not under the ownership or control of, or otherwise affiliated with, the Reporting Person. As a result, those 1,029,511 shares are no longer beneficially owned by the Reporting Person. ( 2 )Shares held directly by Woodland Hills Partner LLC, for which the Reporting Person serves as a managing member. ( 3 )Shares held directly by Shao-Lee Lin 2020 Gift Trust Dtd 7/16/20, for which the Reporting Person's spouse serves as trustee. ( 4 )Shares held directly by Shao-Lee Lin, Trustee of the Shao-Lee Lin Trust u/a/d September 23, 2005, for which the Reporting Person serves as trustee. ( 5 )Shares held directly by Lin Family 2020 Gift Trust Dtd 7/16/20, for which the Reporting Person's spouse shares voting and investment power. ( 6 )Shares held directly by Susie Jun 2020 Gift Trust dtd 7/16/20, for which the Reporting Person serves as trustee. ( 7 )Shares held directly by Susie Jun, Trustee of the Susie Jun Trust U/A/D September 23, 2005, for which the Reporting Person's spouse serves as trustee.

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).

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