{"schema_version":"secwatch.filing_event.v1","accession":"0001193125-25-220479","form_type":"8-K","ticker":"BTC","cik":"0002015034","company_name":"Grayscale Bitcoin Mini Trust ETF","filed_at":"2025-09-26T23:59:59+00:00","discovered_at":"2026-05-14T18:02:45.817044+00:00","generated_at":"2026-05-17T05:37:17.419117+00:00","sec_items":["1.01","9.01"],"event_type":"other_material","sentiment":"neutral","materiality_score":0.55,"calibrated_materiality_score":0.55,"confidence":"high","headline":"Grayscale Bitcoin Mini Trust adds Anchorage Digital as secondary Bitcoin custodian for risk management","bullets":["On Sept 25, 2025, Trust entered Second Amendment to add Anchorage Digital Bank N.A. as custody provider for Bitcoin holdings.","Coinbase remains primary custodian; portion of Bitcoin to be held at Anchorage not yet determined by Sponsor.","Anchorage will store private keys in cold storage, reducing online hacking risk compared to hot storage.","Agreement includes indemnification obligations and requirement for Anchorage to maintain insurance.","Addition reflects Sponsor's ongoing risk management approach given Trust's growing size."],"urls":{"canonical":"https://secwatch.observer/filing/0001193125-25-220479","json":"https://secwatch.observer/filing/0001193125-25-220479.json","markdown":"https://secwatch.observer/filing/0001193125-25-220479.md","text":"https://secwatch.observer/filing/0001193125-25-220479.txt","edgar_index":"https://www.sec.gov/Archives/edgar/data/2015034/000119312525220479/0001193125-25-220479-index.htm","edgar_primary_document":"https://www.sec.gov/Archives/edgar/data/2015034/000119312525220479/btc-20250926.htm"},"model":{"generated_by":"deepseek-v4-flash:cloud@v2","generated_at":"2026-05-17T05:37:17.419117+00:00"},"review":{"review_status":"machine_generated","human_reviewed":false,"corrected":false,"correction_note":null,"correction_timestamp":null,"superseded_by":null,"related_filings":[]},"source_grounded_claims":[],"license":"Source filings: public domain (SEC EDGAR). Summaries (headline + bullets): CC-BY-4.0; attribute https://secwatch.observer"}