---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-23-139427"
form_type: "8-K"
ticker: null
cik: "0001962918"
company_name: "ACELYRIN, Inc."
filed_at: "2023-05-09T23:59:59+00:00"
generated_at: "2026-06-15T10:30:04.155223+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.85
calibrated_materiality_score: 0.85
confidence: "high"
source: SEC EDGAR
---

# ACELYRIN closes upsized IPO, raises $621M; shares begin trading on Nasdaq

## Summary
- Closed IPO of 34,500,000 shares at $18.00 per share, including full exercise of underwriters' option for 4,500,000 additional shares.
- Gross proceeds of $621.0 million before underwriting discounts and expenses.
- Shares began trading on Nasdaq Global Select Market on May 5, 2023 under ticker SLRN.
- Joint book-running managers: Morgan Stanley, Jefferies, TD Cowen, and Piper Sandler.

## SEC filing metadata
- accession: 0001193125-23-139427
- form_type: 8-K
- cik: 0001962918
- company_name: ACELYRIN, Inc.
- filed_at: 2023-05-09T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.85
- calibrated_materiality_score: 0.85
- confidence: high
- sec_items: 5.03, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1962918/000119312523139427/0001193125-23-139427-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1962918/000119312523139427/d444368d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-23-139427
- JSON: https://secwatch.observer/filing/0001193125-23-139427.json
- Plain text: https://secwatch.observer/filing/0001193125-23-139427.txt

## Key facts
- Governance Changes
  ACELYRIN, Inc.: Filed amended and restated certificate of incorporation in connection with IPO closing, effective upon closing of the IPO (effective 2023-05-09).
  - Change: charter amendment
  - Effective: 2023-05-09
  source text: the Company filed an amended and restated certificate of incorporation (the “Restated Certificate”) with the Secretary of State of the State of Delaware
  evidence_url: https://www.sec.gov/Archives/edgar/data/1962918/000119312523139427/0001193125-23-139427-index.htm
- Governance Changes
  ACELYRIN, Inc.: Adopted amended and restated bylaws effective upon IPO closing (effective 2023-05-09).
  - Change: bylaw amendment
  - Effective: 2023-05-09
  source text: Effective as of May 9, 2023, the Company adopted amended and restated bylaws (the “Restated Bylaws”) in connection with the closing of the IPO
  evidence_url: https://www.sec.gov/Archives/edgar/data/1962918/000119312523139427/0001193125-23-139427-index.htm

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.