---
schema_version: "secwatch.filing_event.v1"
accession: "0000950170-25-105826"
form_type: "8-K"
ticker: "GBTC"
cik: "0001588489"
company_name: "Grayscale Bitcoin Trust ETF"
filed_at: "2025-08-08T23:59:59+00:00"
generated_at: "2026-05-17T16:35:54.699200+00:00"
event_type: "other_material"
sentiment: "neutral"
materiality_score: 0.45
calibrated_materiality_score: 0.45
confidence: "high"
source: SEC EDGAR
---

# Grayscale Bitcoin Trust adds Anchorage Digital as secondary Bitcoin custodian

## Summary
- Entered custodial agreement with Anchorage Digital Bank N.A. on Aug 8, 2025 for Bitcoin custody.
- Anchorage will store Bitcoin private keys in cold storage; Coinbase remains primary custodian.
- Sponsor has not yet determined amount of Bitcoin to move to Anchorage.
- Agreement also covers Grayscale Ethereum Trust ETF as additional client.
- Anchorage is a national trust bank chartered by OCC; agreement includes indemnification and insurance.

## SEC filing metadata
- accession: 0000950170-25-105826
- form_type: 8-K
- ticker: GBTC
- cik: 0001588489
- company_name: Grayscale Bitcoin Trust ETF
- filed_at: 2025-08-08T23:59:59+00:00
- event_type: other_material
- sentiment: neutral
- materiality_score: 0.45
- calibrated_materiality_score: 0.45
- confidence: high
- sec_items: 1.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1588489/000095017025105826/0000950170-25-105826-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1588489/000095017025105826/gbtc-20250808.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0000950170-25-105826
- JSON: https://secwatch.observer/filing/0000950170-25-105826.json
- Plain text: https://secwatch.observer/filing/0000950170-25-105826.txt

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