{"schema_version":"secwatch.filing_event.v1","accession":"0000950170-23-049068","form_type":"8-K","ticker":"THG","cik":"0000944695","company_name":"HANOVER INSURANCE GROUP, INC.","filed_at":"2023-09-21T23:59:59+00:00","discovered_at":"2026-05-14T18:03:37.101350+00:00","generated_at":"2026-06-10T11:38:04.255828+00:00","sec_items":["5.03","8.01","9.01"],"event_type":"other_material","sentiment":"neutral","materiality_score":0.3,"calibrated_materiality_score":0.3,"confidence":"high","headline":"Hanover Insurance amends bylaws, plans to propose board declassification at 2024 meeting","bullets":["Bylaws amended to add exclusive forum provision for Delaware courts and conform stockholder list rules to Delaware law.","Board expects to propose declassification of board structure at 2024 annual meeting, moving from staggered three-year terms.","Amendments effective September 19, 2023; declassification proposal subject to stockholder vote at 2024 annual meeting."],"urls":{"canonical":"https://secwatch.observer/filing/0000950170-23-049068","json":"https://secwatch.observer/filing/0000950170-23-049068.json","markdown":"https://secwatch.observer/filing/0000950170-23-049068.md","text":"https://secwatch.observer/filing/0000950170-23-049068.txt","edgar_index":"https://www.sec.gov/Archives/edgar/data/944695/000095017023049068/0000950170-23-049068-index.htm","edgar_primary_document":"https://www.sec.gov/Archives/edgar/data/944695/000095017023049068/thg-20230919.htm"},"model":{"generated_by":"deepseek-v4-flash:cloud@v2","generated_at":"2026-06-10T11:38:04.255828+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":[{"claim_id":"c413c92605bb24d43be21abddbc939f92303e4a8","claim":"HANOVER INSURANCE GROUP, INC.: Amended by-laws to revise stockholder list provision and add an exclusive forum provision for certain legal actions (effective 2023-09-19).","evidence_excerpt":"On September 19, 2023, as part of its periodic review of corporate governance matters, the board of directors (the “Board”) of the Hanover Insurance Group, Inc. (the “Company”) approved and adopted amendments to the Company’s by-laws (as so amended and restated, the “By-laws”), which became effective immediately (the “By-law Amendments”).","evidence_source":"SEC 8-K Item 5.03/5.05/5.06","evidence_url":"https://www.sec.gov/Archives/edgar/data/944695/000095017023049068/0000950170-23-049068-index.htm","confidence":0.9,"family_label":"Governance Changes","details":[{"label":"Change","value":"bylaw amendment"},{"label":"Effective","value":"2023-09-19"}],"fact_type":"governance_change"}],"license":"Source filings: public domain (SEC EDGAR). Summaries (headline + bullets): CC-BY-4.0; attribute https://secwatch.observer"}