---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-25-199686"
form_type: "8-K"
ticker: "ALNY"
cik: "0001178670"
company_name: "ALNYLAM PHARMACEUTICALS, INC."
filed_at: "2025-09-10T23:59:59+00:00"
generated_at: "2026-05-17T06:57:47.157913+00:00"
event_type: "debt"
sentiment: "neutral"
materiality_score: 0.65
calibrated_materiality_score: 0.65
confidence: "high"
source: SEC EDGAR
---

# Alnylam prices $575M zero-coupon convertible notes due 2028; repurchases $637.8M of 2027 notes

## Summary
- $575M principal of 0.00% convertible senior notes due 2028 priced; initial conversion price ~$670.11/share, 40% premium to VWAP.
- Net proceeds ~$561.6M; ~$30.7M used for capped call transactions with cap price ~$837.61/share (75% premium).
- Concurrently repurchased ~$637.8M of existing 1.00% convertible notes due 2027 for ~$1,105.8M including accrued interest.
- Offering upsized from earlier $500M announcement; initial purchasers have option for additional $86.25M.
- Closing expected Sept 12, 2025; notes mature Sept 15, 2028; redeemable after Sept 20, 2027 if stock >130% conversion price.

## SEC filing metadata
- accession: 0001193125-25-199686
- form_type: 8-K
- ticker: ALNY
- cik: 0001178670
- company_name: ALNYLAM PHARMACEUTICALS, INC.
- filed_at: 2025-09-10T23:59:59+00:00
- event_type: debt
- sentiment: neutral
- materiality_score: 0.65
- calibrated_materiality_score: 0.65
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1178670/000119312525199686/0001193125-25-199686-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1178670/000119312525199686/d72540d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-25-199686
- JSON: https://secwatch.observer/filing/0001193125-25-199686.json
- Plain text: https://secwatch.observer/filing/0001193125-25-199686.txt

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