{"schema_version":"secwatch.filing_event.v1","accession":"0001193125-26-108382","form_type":"8-K","ticker":"GBTC","cik":"0001588489","company_name":"Grayscale Bitcoin Trust ETF","filed_at":"2026-03-16T23:59:59+00:00","discovered_at":"2026-05-14T18:02:35.557112+00:00","generated_at":"2026-05-15T11:44:38.486592+00:00","sec_items":["8.01"],"event_type":"other_material","sentiment":"neutral","materiality_score":0.4,"calibrated_materiality_score":0.4,"confidence":"high","headline":"Grayscale Bitcoin Trust to switch Bitcoin benchmark to CoinDesk Bitcoin Benchmark Rate on Apr 1","bullets":["Effective April 1, 2026, GBTC will value Bitcoin using CoinDesk Bitcoin Benchmark Rate, replacing CoinDesk Bitcoin Price Index (XBX).","New benchmark uses data from 11 exchanges: Binance, Bitstamp, Bullish, Bybit, Crypto.com, Gate, Gemini, HashKey, Kraken, LMAX Digital, OKX.","Methodology includes volume weighting, outlier detection, inactivity adjustment, and manipulation resistance to mitigate fraud.","If primary index is unavailable, cascading rules fall back to Coin Metrics Real-Time Rate, then principal market price, then Sponsor's estimate.","The change is operational only; no immediate impact on Bitcoin holdings or share structure."],"urls":{"canonical":"https://secwatch.observer/filing/0001193125-26-108382","json":"https://secwatch.observer/filing/0001193125-26-108382.json","markdown":"https://secwatch.observer/filing/0001193125-26-108382.md","text":"https://secwatch.observer/filing/0001193125-26-108382.txt","edgar_index":"https://www.sec.gov/Archives/edgar/data/1588489/000119312526108382/0001193125-26-108382-index.htm","edgar_primary_document":"https://www.sec.gov/Archives/edgar/data/1588489/000119312526108382/gbtc-20260316.htm"},"model":{"generated_by":"deepseek-v4-flash:cloud@v2","generated_at":"2026-05-15T11:44:38.486592+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"}