# WHITE MOUNTAINS INSURANCE GROUP LTD — SC TO-I/A

WHITE MOUNTAINS INSURANCE GROUP LTD of HANOVER, NH filed a SC TO-I/A with the SEC on 2025-12-22. Industry: Fire, Marine & Casualty Insurance.

## Filing

- Filed: 2025-12-22
- Form: SC TO-I/A
- Accession: 0001104659-25-123514
- Registrant: WHITE MOUNTAINS INSURANCE GROUP LTD
- CIK: 0000776867
- Industry (SIC): Fire, Marine & Casualty Insurance (6331)
- State of incorporation: D0
- Location: HANOVER, NH

## Documents (3)

| Seq | Type | Description |
| --- | --- | --- |
| 1 | SC TO-I/A | SC TO-I/A |
| 2 | EX-99.(A)(5)(O) | EXHIBIT 99.(A)(5)(O) |
| 3 | GRAPHIC | GRAPHIC |

## Filing timeline for this registrant (60)

_Showing 12 of 60 filings._

| Filed | Form |
| --- | --- |
| [2026-04-01](https://search.stillhousedata.com/proxy/0001104659-26-038487) | DEF 14A |
| [2025-12-29](https://search.stillhousedata.com/proxy/0001104659-25-124380) | SC TO-I/A |
| 2025-12-22 | SC TO-I/A |
| [2025-11-21](https://search.stillhousedata.com/proxy/0001104659-25-114719) | SC TO-I |
| [2025-04-02](https://search.stillhousedata.com/proxy/0001104659-25-031124) | DEF 14A |
| [2024-04-04](https://search.stillhousedata.com/proxy/0001104659-24-043314) | DEF 14A |
| [2023-05-10](https://search.stillhousedata.com/proxy/0000776867-23-000007) | DEFA14A |
| [2023-04-06](https://search.stillhousedata.com/proxy/0001104659-23-042418) | DEFR14A |
| [2023-04-05](https://search.stillhousedata.com/proxy/0001104659-23-042136) | DEF 14A |
| [2022-09-26](https://search.stillhousedata.com/proxy/0001104659-22-102831) | SC TO-I/A |
| [2022-09-21](https://search.stillhousedata.com/proxy/0001104659-22-101757) | SC TO-I/A |
| [2022-08-30](https://search.stillhousedata.com/proxy/0001104659-22-095834) | SC TO-I/A |

## More

- [CIK 776867 on SEC EDGAR (source of record)](https://www.sec.gov/cgi-bin/browse-edgar?action=getcompany&CIK=776867&type=&dateb=&owner=include&count=40)
- [This page as markdown (for LLM agents)](https://search.stillhousedata.com/proxy/0001104659-25-123514.md)
- [Search all SEC filings, advisers and people on Adviser Search](https://search.stillhousedata.com/)

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