---
schema_version: "secwatch.filing_event.v1"
accession: "0001628280-25-055388"
form_type: "8-K"
ticker: "MRK"
cik: "0000310158"
company_name: "Merck & Co., Inc."
filed_at: "2025-12-04T23:59:59+00:00"
generated_at: "2026-05-16T14:57:48.464512+00:00"
event_type: "debt"
sentiment: "neutral"
materiality_score: 0.65
calibrated_materiality_score: 0.65
confidence: "high"
source: SEC EDGAR
---

# Merck closes $8.0B multi-tranche debt offering across eight series

## Summary
- Total $8.0B includes Floating Rate Notes due 2029 ($500M), 3.850% Notes due 2029 ($750M), 4.150% due 2031 ($1B), 4.450% due 2032 ($1B).
- Also $1.5B 4.750% Notes due 2035, $750M 5.500% due 2046, $1.5B 5.550% due 2055, and $1.0B 5.700% due 2065.
- Offering closed December 4, 2025 under existing shelf registration statement (333-278066).
- Proceeds not specified; notes are senior unsecured obligations issued under indenture dated Jan. 6, 2010.

## SEC filing metadata
- accession: 0001628280-25-055388
- form_type: 8-K
- ticker: MRK
- cik: 0000310158
- company_name: Merck & Co., Inc.
- filed_at: 2025-12-04T23:59:59+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/310158/000162828025055388/0001628280-25-055388-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/310158/000162828025055388/mrk-20251204.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001628280-25-055388
- JSON: https://secwatch.observer/filing/0001628280-25-055388.json
- Plain text: https://secwatch.observer/filing/0001628280-25-055388.txt

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