---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-26-222908"
form_type: "8-K"
ticker: "BIIB"
cik: "0000875045"
company_name: "BIOGEN INC."
filed_at: "2026-05-14T12:31:16+00:00"
generated_at: "2026-05-14T12:36:26.298772+00:00"
event_type: "m_and_a"
sentiment: "positive"
materiality_score: 0.95
calibrated_materiality_score: 0.95
confidence: "high"
source: SEC EDGAR
---

# Biogen completes $5.3B Apellis acquisition; adds SYFOVRE/EMPAVELI, $41/share + CVRs

## Summary
- Biogen acquired Apellis for $41/share cash plus CVRs worth up to $4/share tied to SYFOVRE net sales milestones.
- Approximately 105.7M shares (82.4%) tendered; Merger completed under DGCL Section 251(h) without shareholder vote.
- Biogen borrowed $2B under a new credit agreement: $1B 364-day and $1B 2-year tranches to fund the acquisition.
- Apellis products EMPAVELI and SYFOVRE generated $689M net product revenue in 2025; deal expected to be accretive to Non-GAAP EPS in 2027.
- Biogen will provide updated financial guidance in Q2 2026 earnings report in July.

## SEC filing metadata
- accession: 0001193125-26-222908
- form_type: 8-K
- ticker: BIIB
- cik: 0000875045
- company_name: BIOGEN INC.
- filed_at: 2026-05-14T12:31:16+00:00
- event_type: m_and_a
- sentiment: positive
- materiality_score: 0.95
- calibrated_materiality_score: 0.95
- confidence: high
- sec_items: 1.01, 2.01, 2.03, 7.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/875045/000119312526222908/0001193125-26-222908-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/875045/000119312526222908/d109852d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-26-222908
- JSON: https://secwatch.observer/filing/0001193125-26-222908.json
- Plain text: https://secwatch.observer/filing/0001193125-26-222908.txt

## Key facts
- Debt Financings
  BIOGEN INC. incurred term loan of $1 billion with U.S. Bank National Association at Term SOFR plus an applicable margin ranging from 0.750% to 1.000% maturing May 12, 2028.
  - Instrument: term loan
  - Principal: $1 billion
  - Counterparty: U.S. Bank National Association
  - Rate: Term SOFR plus an applicable margin ranging from 0.750% to 1.000%
  - Maturity: May 12, 2028
  - Event: incurrence
  source text: The Credit Agreement provides for unsecured term loan facilities in an aggregate principal amount of $2 billion (the “Term Facilities”), comprised of a $1 billion 364-day tranche (“Tranche A”) and a $1 billion two-year tranche (“Tranche B”).
  evidence_url: https://www.sec.gov/Archives/edgar/data/875045/000119312526222908/0001193125-26-222908-index.htm
- Debt Financings
  BIOGEN INC. incurred term loan of $1 billion with U.S. Bank National Association at Term SOFR plus an applicable margin of 0.750% or Base Rate plus an applicable ma maturing May 12, 2027.
  - Instrument: term loan
  - Principal: $1 billion
  - Counterparty: U.S. Bank National Association
  - Rate: Term SOFR plus an applicable margin of 0.750% or Base Rate plus an applicable ma
  - Maturity: May 12, 2027
  - Event: incurrence
  source text: The Credit Agreement provides for unsecured term loan facilities in an aggregate principal amount of $2 billion (the “Term Facilities”), comprised of a $1 billion 364-day tranche (“Tranche A”) and a $1 billion two-year tranche (“Tranche B”).
  evidence_url: https://www.sec.gov/Archives/edgar/data/875045/000119312526222908/0001193125-26-222908-index.htm
- M&A Transactions
  BIOGEN INC. completed an acquisition involving Apellis Pharmaceuticals, Inc. for Cash Amount of $41.00 per Share plus one CVR per Share representing contingent cash payments of up to an aggregate of $4.00 per Share (closed 2026-05-14).
  - Action: acquisition
  - Counterparty: Apellis Pharmaceuticals, Inc.
  - Consideration: Cash Amount of $41.00 per Share plus one CVR per Share representing contingent cash payments of up to an aggregate of $4.00 per Share
  - Closing: 2026-05-14
  source text: CVR Agreement As previously disclosed, on March 31, 2026, Biogen Inc., a Delaware corporation (“Biogen”), entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Apellis Pharmaceuticals, Inc., a Delaware corporation (“Apellis”), and Aspen Purchaser Sub, Inc., a Delaware corporation and a wholly owned subsidiary of Biogen (“Purchaser”).
  evidence_url: https://www.sec.gov/Archives/edgar/data/875045/000119312526222908/0001193125-26-222908-index.htm

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