Beth C. Seidenberg - 09 May 2023 Form 4 Insider Report for ACELYRIN, Inc. (SLRN)

Role: Director, 10%+ Owner
Signature: /s/ Mina Kim, Attorney-in-fact
Issuer symbol: SLRN
Transactions as of: 09 May 2023
Net transactions value: +$23,580,000
Form type: 4
Filing time: 11 May 2023, 21:13:53 UTC
Previous filing: 04 May 2023
Next filing: 12 May 2023
SEC: View on sec.gov

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	SLRN	Common Stock	Conversion of derivative security		+8,540,729			8,540,729	09 May 2023	See footnote	F1, F2
transaction	SLRN	Common Stock	Purchase	$22,500,000	+1,250,000	+15%	$18.00	9,790,729	09 May 2023	See footnote	F2, F3
transaction	SLRN	Common Stock	Purchase	$1,080,000	+60,000		$18.00	60,000	09 May 2023	Direct	F4

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	SLRN	Series A Redeemable Convertible Preferred Stock	Conversion of derivative security		-4,056,795	-100%		0	09 May 2023	Common Stock	4,056,795		See footnote	F2, F5, F6
transaction	SLRN	Series B Redeemable Convertible Preferred Stock	Conversion of derivative security		-2,445,786	-100%		0	09 May 2023	Common Stock	2,445,786		See footnote	F2, F5, F6
transaction	SLRN	Series C Redeemable Convertible Preferred Stock	Conversion of derivative security		-2,038,148	-100%		0	09 May 2023	Common Stock	2,038,148		See footnote	F2, F5, F6
transaction	SLRN	Director Stock Option (right to buy)	Other	$0	-23,243	-100%	$0.000000^*	0	09 May 2023	Class A Common Stock	23,243	$18.00	Direct	F6, F7
transaction	SLRN	Director Stock Option (right to buy)	Other	$0	+23,243		$0.000000	23,243	09 May 2023	Common Stock	23,243	$18.00	Direct	F6, F7

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	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.
F2	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.
F3	Represents shares of Common Stock purchased in the Issuer's initial public offering of Common Stock (the "IPO").
F4	Represents shares of Common Stock purchased through a directed share program in the IPO.
F5	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.
F6	Each share of Class A Common Stock was reclassified into one share of Common Stock immediately prior to the completion of the IPO.
F7	1/36 of the shares subject to the option vest on June 4, 2023, and 1/36 of the shares subject to the option vest in equal monthly installments thereafter, subject to the Reporting Person's continued service.