Shephard Mpofu - 21 May 2025 Form 4 Insider Report for ACELYRIN, Inc. (SLRN)

Reporting relationship: Chief Medical Officer
Issuer ticker: SLRN
Reported as of: 21 May 2025
Net transaction value: $0
SEC form: 4
Accepted by SEC: 23 May 2025, 16:08:30 UTC
Prior SEC filing: 19 Mar 2025
Source filing: View source filing
Reporting owner signature: /s/ Eddie Kim, Attorney-in-fact

Key filing fact

Shephard Mpofu filed Form 4 for ACELYRIN, Inc. (SLRN) on 23 May 2025.

Key facts

This page summarizes Shephard Mpofu's Form 4 filing for ACELYRIN, Inc. (SLRN).
4 reported transactions and 3 derivative rows are listed below.
Accepted by SEC: 23 May 2025, 16:08.

Change

Previous filing in this sequence was filed on 19 Mar 2025.
Current net transaction value: $0.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0002023809 Primary reporting owner

Mpofu Shephard

Relationship: Chief Medical Officer
Address: C/O ACELYRIN, INC., 4149 LIBERTY CANYON RD., AGOURA HILLS
Signature: /s/ Eddie Kim, Attorney-in-fact
Signature date: 23 May 2025

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

SLRN transaction

Common Stock

Disposed to Issuer

Transaction value
Shares: -121,789
Change %: -100%
Price
Shares after: 0
Date: 21 May 2025
Ownership: Direct
Footnotes: F1, F2

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

SLRN transaction Derivative

Employee Stock Option (right to buy)

Disposed to Issuer

Transaction value
Shares: -328,860
Change %: -100%
Price
Shares after: 0
Date: 21 May 2025
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 328,860
Exercise price: $4.22
Footnotes: F3, F4

SLRN transaction Derivative

Employee Stock Option (right to buy)

Disposed to Issuer

Transaction value
Shares: -142,586
Change %: -100%
Price
Shares after: 0
Date: 21 May 2025
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 142,586
Exercise price: $7.68
Footnotes: F4, F5

SLRN transaction Derivative

Employee Stock Option (right to buy)

Disposed to Issuer

Transaction value
Shares: -118,858
Change %: -100%
Price
Shares after: 0
Date: 21 May 2025
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 118,858
Exercise price: $10.17
Footnotes: F4, F6

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Section 16 status

Shephard Mpofu is no longer subject to Section 16 filing requirements. Form 4 or Form 5 obligations may still apply in specific circumstances.

Explanation of responses 6 footnotes

Footnote F1

On February 6, 2025, ACELYRIN, Inc., a Delaware corporation (the "Company"), entered into an Agreement and Plan of Merger (as amended on April 20, 2025, the "Merger Agreement") with Alumis, Inc., a Delaware corporation ("Parent"), and Arrow Merger Sub, Inc., a Delaware corporation and wholly owned subsidiary of Parent ("Merger Sub"). Pursuant to the Merger Agreement, on May 21, 2025, Merger Sub merged with and into the Company (the "Merger"), with the Company surviving as a wholly owned subsidiary of Parent. At the effective time of the Merger (the "Effective Time"), each share of common stock, par value $0.00001 per share, of the Company issued and outstanding was converted into the right to receive 0.4814 (the "Exchange Ratio") shares of voting common stock of Parent, par value $0.0001 per share ("Parent Common Stock"), and cash in lieu of any fractional shares.

Footnote F2

(Continued from Footnote 1) Pursuant to the Merger Agreement, at the Effective Time, each outstanding and unvested restricted stock unit ("RSU") immediately prior to the Effective Time was assumed by Parent and converted into an RSU award with respect to a number of shares of Parent Common Stock equal to (i) the total number of shares subject to the RSU immediately prior to the Effective Time multiplied by (ii) the Exchange Ratio, with any fractional shares rounded down to the nearest whole share. At the Effective Time, each outstanding and vested RSU immediately prior the Effective Time, including any RSU that became vested as a result of the Merger, was cancelled and converted into the right to receive the number of shares of Parent Common Stock equal to (i) the total number of shares subject to the RSU immediately prior to the Effective Time multiplied by (ii) the Exchange Ratio, with any fractional shares rounded down to the nearest whole share.

Footnote F3

1/4 of the shares subject to the option vest on May 23, 2025, and 1/48 of the shares subject to the option vests in equal monthly installments thereafter, subject to the Reporting Person's continued service.

Footnote F4

Pursuant to the Merger Agreement, at the Effective Time each stock option that was outstanding and unexercised immediately prior to the Effective Time with a per share exercise price of $18.00 or less was assumed by Parent and converted into an option to purchase a number of shares of Parent Common Stock equal to (i) the number of shares subject to the option immediately prior to the Effective Time, multiplied by (ii) the Exchange Ratio, with any fractional shares rounded down to the nearest whole share, which stock option shall have an exercise price equal to (i) the per share exercise price for shares subject to the corresponding Company stock option immediately prior to the Effective Time, divided by (ii) the Exchange Ratio, rounded up to the nearest whole cent.

Footnote F5

1/4 of the shares subject to the option vested on January 9, 2025, and 1/48 of the shares subject to the option vests in equal monthly installments thereafter, subject to the Reporting Person's continued service.

Footnote F6

1/4 of the shares subject to the option vested on September 25, 2024 and 1/48 of the shares subject to the option vest in equal monthly installments thereafter, subject to the Reporting Person's continued service.