{"schema_version":"secwatch.filing_event.v1","accession":"0000776867-25-000012","form_type":"8-K","ticker":"WTM","cik":"0000776867","company_name":"WHITE MOUNTAINS INSURANCE GROUP LTD","filed_at":"2025-07-18T23:59:59+00:00","discovered_at":"2026-05-14T18:02:46.353500+00:00","generated_at":"2026-05-18T05:52:42.386543+00:00","sec_items":["8.01","9.01"],"event_type":"other_material","sentiment":"neutral","materiality_score":0.6,"calibrated_materiality_score":0.6,"confidence":"high","headline":"White Mountains closes $150M strategic investment in BroadStreet Partners","bullets":["White Mountains invested $150M in BroadStreet as part of a group led by Ethos Capital, BCI, and T. Rowe Price.","Ontario Teachers' retains a significant co-control stake and continues partnership with the Ethos-led group.","BroadStreet is a middle-market insurance brokerage offering commercial and personal P&C and employee benefits solutions.","Investment aims to support BroadStreet's Core Agency Partners with M&A, capital solutions, and digital transformation tools."],"urls":{"canonical":"https://secwatch.observer/filing/0000776867-25-000012","json":"https://secwatch.observer/filing/0000776867-25-000012.json","markdown":"https://secwatch.observer/filing/0000776867-25-000012.md","text":"https://secwatch.observer/filing/0000776867-25-000012.txt","edgar_index":"https://www.sec.gov/Archives/edgar/data/776867/000077686725000012/0000776867-25-000012-index.htm","edgar_primary_document":"https://www.sec.gov/Archives/edgar/data/776867/000077686725000012/wtm-20250718.htm"},"model":{"generated_by":"deepseek-v4-flash:cloud@v2","generated_at":"2026-05-18T05:52:42.386543+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"}