WTM SEC Filings: 8-K, 10-Q, S-3 & 424B

Financials

TYPE

HEADLINE

FILED AT

10-Q

Form 10-Q - Quarterly report [Sections 13 or 15(d)]

Nov 5, 2026

10-Q

Form 10-Q - Quarterly report [Sections 13 or 15(d)]

Aug 6, 2026

11-K

Form 11-K - Annual report of employee stock purchase, savings and similar plans

Jun 29, 2026

10-Q

Form 10-Q - Quarterly report [Sections 13 or 15(d)]

May 6, 2026

10-K

Form 10-K - Annual report [Section 13 and 15(d), not S-K Item 405]

Feb 27, 2026

10-Q

Form 10-Q - Quarterly report [Sections 13 or 15(d)]

Nov 6, 2025

News

TYPE

HEADLINE

FILED AT

8-K

White Mountains Reports Third Quarter 2026 Results

Nov 5, 2026

8-K

Stephen Klar Elected to the White Mountains Board of Directors

Aug 27, 2026

8-K

White Mountains Reports Second Quarter 2026 Financial Results

Aug 6, 2026

8-K

White Mountains Insurance Group 2026 Annual Investor Presentation

Jun 5, 2026

8-K

White Mountains Insurance Group, Ltd. Announces 2026 Annual General Meeting Results and Director Departure

May 21, 2026

8-K

White Mountains Insurance Group Subsidiary Completes $200 Million Private Placement of Senior Secured Notes

May 15, 2026

Prospectus

TYPE

HEADLINE

FILED AT

424B3

Form 424B3 - Prospectus [Rule 424(b)(3)]

May 16, 2003

424B3

Form 424B3 - Prospectus [Rule 424(b)(3)]

May 12, 2003

424B3

Form 424B3 - Prospectus [Rule 424(b)(3)]

Apr 6, 1999

424B3

Form 424B3 - Prospectus [Rule 424(b)(3)]

Mar 5, 1997

Registrations

TYPE

HEADLINE

FILED AT

SC TO-I/A

Form SC TO-I/A - Tender offer statement by Issuer: [Amend]

Dec 29, 2025

SC TO-I/A

Form SC TO-I/A - Tender offer statement by Issuer: [Amend]

Dec 22, 2025

SC TO-I

Form SC TO-I - Tender offer statement by Issuer

Nov 21, 2025

SC TO-T/A

Form SC TO-T/A - Tender offer statement by Third Party: [Amend]

Jun 30, 2023

SC TO-T/A

Form SC TO-T/A - Tender offer statement by Third Party: [Amend]

Jun 27, 2023

SC TO-T

Form SC TO-T - Tender offer statement by Third Party

May 26, 2023

Proxies

TYPE

HEADLINE

FILED AT

N-PX

Form N-PX - Annual Report of proxy voting record of management investment companies

Aug 26, 2026

DEF 14A

Form DEF 14A - Other definitive proxy statements

Apr 1, 2026

N-PX

Form N-PX - Annual Report of proxy voting record of management investment companies

Aug 27, 2025

DEF 14A

Form DEF 14A - Other definitive proxy statements

Apr 2, 2025

N-PX

Form N-PX - Annual Report of proxy voting record of management investment companies

Aug 29, 2024

DEF 14A

Form DEF 14A - Other definitive proxy statements

Apr 4, 2024

Ownerships

TYPE

HEADLINE

FILED AT

SCHEDULE 13D/A

WHITE MOUNTAINS INSURANCE GROUP LTD (Filed by)

Nov 5, 2026

WHITE MOUNTAINS INSURANCE GROUP LTD (Reporting)

Nov 5, 2026

SCHEDULE 13D/A

WHITE MOUNTAINS INSURANCE GROUP LTD (Filed by)

Oct 30, 2026

Tanner David Allen (Reporting)

Aug 31, 2026

Klar Stephen (Reporting)

Aug 27, 2026

Klar Stephen (Reporting)

Aug 27, 2026

Other

TYPE

HEADLINE

FILED AT

LETTER

Form UPLOAD - SEC-generated letter

Jun 17, 2020

CORRESP

Form CORRESP - Correspondence

Jun 10, 2020

LETTER

Form UPLOAD - SEC-generated letter

May 28, 2020

LETTER

Form UPLOAD - SEC-generated letter

Feb 22, 2013

CORRESP

Form CORRESP - Correspondence

Feb 19, 2013

CORRESP

Form CORRESP - Correspondence

Jan 18, 2013

White Mountains Insurance Group, Ltd. WTM · SEC Filings