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* Westlake BioPartners Fund II, L.P. (Last) (First) (Middle) C/O WESTLAKE BIOPARTNERS, LLC 3075 TOWNSGATE RD., SUITE 140 (Street) WESTLAKE VILLAGE CA 91361 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol ACELYRIN, Inc. [ SLRN ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 05/09/2023
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person
	Rule 10b5-1(c) Transaction Indication Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

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	05/09/2023		C(1)		8,540,729	A	(1)	8,540,729	D(2)(3)
Common Stock	05/09/2023		P(4)		1,250,000	A	$18	9,790,729	D(2)(3)

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
Series A Redeemable Convertible Preferred Stock	(5)	05/09/2023		C			4,056,795	(5)	(5)	Common Stock(6)	4,056,795	(5)	0	D(2)(3)
Series B Redeemable Convertible Preferred Stock	(5)	05/09/2023		C			2,445,786	(5)	(5)	Common Stock(6)	2,445,786	(5)	0	D(2)(3)
Series C Redeemable Convertible Preferred Stock	(5)	05/09/2023		C			2,038,148	(5)	(5)	Common Stock(6)	2,038,148	(5)	0	D(2)(3)

1. Name and Address of Reporting Person* Westlake BioPartners Fund II, L.P. (Last) (First) (Middle) C/O WESTLAKE BIOPARTNERS, LLC 3075 TOWNSGATE RD., SUITE 140 (Street) WESTLAKE VILLAGE CA 91361 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Westlake BioPartners GP II, LLC (Last) (First) (Middle) C/O WESTLAKE BIOPARTNERS, LLC 3075 TOWNSGATE RD., SUITE 140 (Street) WESTLAKE VILLAGE CA 91361 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Harper Sean E (Last) (First) (Middle) C/O WESTLAKE BIOPARTNERS, LLC 3075 TOWNSGATE RD., SUITE 140 (Street) WESTLAKE VILLAGE CA 91361 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. Represents shares of Common Stock received upon conversion of shares of the reported series of preferred stock on a one-for-one basis without payment of further consideration.

2. 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. Beth C. Seidenberg 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.

3. This report on Form 4 is jointly filed by Westlake Fund II, Westlake GP II and Sean E. Harper. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of such person's or entity's pecuniary interest therein, if any. Westlake Fund II has designated a representative, Beth C. Seidenberg, a Managing Director of Westlake GP II, to serve on the Issuer's board of directors. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for the purposes of Section 16 of the Exchange Act, or for any other purpose.

4. Represents shares of Common Stock purchased in the Issuer's initial public offering of Common Stock (the "IPO").

5. Each share of preferred stock is convertible into one share of Common Stock and has no expiration date. Immediately prior to the completion of the IPO, all shares of preferred stock automatically converted into shares of Common Stock.

6. Each share of Class A Common Stock was reclassified into one share of Common Stock immediately prior to the completion of the IPO.

Remarks:

	/s/ Jennifer L. Kercher, Attorney-in-fact	05/11/2023
	** 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).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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