---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-25-202366"
form_type: "8-K"
ticker: "ALNY"
cik: "0001178670"
company_name: "ALNYLAM PHARMACEUTICALS, INC."
filed_at: "2025-09-12T23:59:59+00:00"
generated_at: "2026-05-17T06:43:20.131883+00:00"
event_type: "debt"
sentiment: "neutral"
materiality_score: 0.7
calibrated_materiality_score: 0.7
confidence: "high"
source: SEC EDGAR
---

# Alnylam issues $661.25M zero-coupon convertible notes due 2028; repurchases $637.8M of existing notes

## Summary
- Issued $661.25M aggregate principal of 0.00% Convertible Senior Notes due 2028; initial conversion price $670.11/share (~40% premium).
- Capped call transactions entered to offset dilution; cost $35.3M, cap price $837.61/share (~75% premium).
- Repurchased $637.8M of existing 1.00% convertible notes due 2027 for ~$1,105.8M total (including accrued interest).
- Notes mature Sept 15, 2028, no regular interest; settlement in cash, shares, or combination at Alnylam's election.

## SEC filing metadata
- accession: 0001193125-25-202366
- form_type: 8-K
- ticker: ALNY
- cik: 0001178670
- company_name: ALNYLAM PHARMACEUTICALS, INC.
- filed_at: 2025-09-12T23:59:59+00:00
- event_type: debt
- sentiment: neutral
- materiality_score: 0.7
- calibrated_materiality_score: 0.7
- confidence: high
- sec_items: 1.01, 2.03, 3.02, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1178670/000119312525202366/0001193125-25-202366-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1178670/000119312525202366/d949176d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-25-202366
- JSON: https://secwatch.observer/filing/0001193125-25-202366.json
- Plain text: https://secwatch.observer/filing/0001193125-25-202366.txt

## Key facts
- Debt Financings
  ALNYLAM PHARMACEUTICALS, INC. incurred convertible notes of $661.25 million with The Bank of New York Mellon at 0.00% maturing September 15, 2028.
  - Instrument: convertible notes
  - Principal: $661.25 million
  - Counterparty: The Bank of New York Mellon
  - Rate: 0.00%
  - Maturity: September 15, 2028
  - Event: incurrence
  source text: 0.00% Convertible Senior Notes due 2028 (the “Additional Notes” and together with the Initial Notes, the “Notes”), bringing the total aggregate principal amount of the Notes to $661.25 million. The Notes are the Company’s senior unsecured obligations. The Notes were issued pursuant to an Indenture, dated September 12, 2025 (the “Indenture”), between the Company and The
  evidence_url: https://www.sec.gov/Archives/edgar/data/1178670/000119312525202366/0001193125-25-202366-index.htm

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