SEIDENBERG BETH C Form 3 Filed 2023-05-04

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

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 ^*

SEIDENBERG BETH C

2. Date of Event Requiring Statement (Month/Day/Year)

05/04/2023

3. Issuer Name and Ticker or Trading Symbol

ACELYRIN, Inc. [SLRN]

(Last)

(First)

(Middle)

C/O ACELYRIN, INC., 4149 LIBERTY CANYON RD.

4. Relationship of Reporting Person(s) to Issuer

(Check all applicable)

__X__ Director	__X__ 10% Owner
_____ Officer (give title below)	_____ Other (specify below)

5. If Amendment, Date Original Filed (Month/Day/Year)

(Street)

AGOURA HILLS, CA 91301

(City)

(State)

(Zip)

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 Beneficially Owned

1.Title of Security (Instr. 4)

2. Amount of Securities Beneficially Owned (Instr. 4)

3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)

4. Nature of Indirect Beneficial Ownership (Instr. 5)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
1. Title of Derivative Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	4. Conversion or Exercise Price of Derivative Security		6. Nature of Indirect Beneficial Ownership (Instr. 5)
Series A Redeemable Convertible Preferred Stock	⁽¹⁾	⁽¹⁾	Class A Common Stock⁽²⁾	4,056,795	⁽¹⁾	I	See footnote⁽³⁾
Series B Redeemable Convertible Preferred Stock	⁽¹⁾	⁽¹⁾	Class A Common Stock⁽²⁾	2,445,786	⁽¹⁾	I	See footnote⁽³⁾
Series C Redeemable Convertible Preferred Stock	⁽¹⁾	⁽¹⁾	Class A Common Stock⁽²⁾	2,038,148	⁽¹⁾	I	See footnote⁽³⁾

Explanation of Responses:

1.	Each share of preferred stock is convertible into one share of Class A Common Stock or, subject to and in accordance with certain provisions set forth in the Issuer's certificate of incorporation, Class B Common Stock, and has no expiration date. Immediately prior to the completion of the Issuer's initial public offering of Common Stock (the "IPO"), all shares of preferred stock will automatically convert into shares of Common Stock.
2.	Each share of Class A Common Stock shall be reclassified into one share of Common Stock immediately prior to the completion of the IPO.
3.	Shares held directly by Westlake BioPartners Fund II, L.P., or Westlake Fund II. Westlake BioPartners GP II, LLC, or Westlake GP II, is the general partner of Westlake Fund II. Westlake GP II may be deemed to have sole voting and dispositive power with regard to the shares held directly by Westlake Fund II. The Reporting Person and Sean E. Harper are the Managing Directors of Westlake GP II and share voting and dispositive power over the shares held by Westlake Fund II, each of whom disclaims beneficial ownership of the shares held by Westlake Fund II except to the extent of such person's pecuniary interest therein, if any.
Remarks: Exhibit 24 - Power of Attorney

	Signatures
	/s/ Mina Kim, Attorney-in-fact	05/04/2023
	** 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).
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POWER OF ATTORNEY
Know all by these presents, that the undersigned hereby constitutes and appoints
each of Mina Kim, Sanampreet Pangali, Eddie Kim, Charles Kim, Chadwick Mills,
Anitha Anne, and Brian Youn, signing individually, the undersigned's true and
lawful attorneys-in fact and agents to:

(1) execute for and on behalf of the undersigned, in the undersigned's capacity
as an officer, director and/or greater than 10% stockholder of ACELYRIN, Inc.
(the "Company"), Forms 3, 4 and 5 (including any amendments thereto) in
accordance with Section 16(a) of the Securities Exchange Act of 1934, as amended
(the "Exchange Act"), and the rules thereunder;

(2) do and perform any and all acts for and on behalf of the undersigned which
may be necessary or desirable to complete and execute any such Forms 3, 4 or 5
(including any amendments thereto) and timely file such forms with the
Securities and Exchange Commission and any stock exchange or similar authority;
and

(3) take any other action of any nature whatsoever in connection with the
foregoing which, in the opinion of such attorney-in-fact, may be of benefit to,
in the best interest of, or legally required by, the undersigned, it being
understood that the documents executed by such attorney-in-fact on behalf of the
undersigned pursuant to this Power of Attorney shall be in such form and shall
contain such terms and conditions as such attorney-in-fact may approve in such
attorney-in-fact's discretion.

The undersigned hereby grants to each such attorney-in-fact full power and
authority to do and perform any and every act and thing whatsoever requisite,
necessary or proper to be done in the exercise of any of the rights and powers
herein granted, as fully to all intents and purposes as the undersigned might or
could do if personally present, with full power of substitution or revocation,
hereby ratifying and confirming all that such attorney-in-fact, or such
attorney-in-fact's substitute or substitutes, shall lawfully do or cause to be
done by virtue of this power of attorney and the rights and powers herein
granted. The undersigned acknowledges that the foregoing attorneys-in-fact, in
serving in such capacity at the request of the undersigned, are not assuming,
nor is the Company assuming, any of the undersigned's responsibilities to comply
with Section 16 of the Exchange Act.

This Power of Attorney shall remain in full force and effect until the earliest
to occur of (a) the undersigned is no longer required to file Forms 3, 4 and 5
with respect to the undersigned's holdings of and transactions in securities
issued by the Company, (b) revocation by the undersigned in a signed writing
delivered to the foregoing attorneys-in-fact or (c) as to any attorney-in-fact
individually, until such attorney-in-fact is no longer employed by the Company
or employed by or a partner at Cooley LLP, as applicable.

The undersigned has caused this Power of Attorney to be executed as of April 10,
2023.

/s/ Beth Seidenberg