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WHITE MOUNTAINS INSURANCE GROUP, LTD: filings

Every WHITE MOUNTAINS INSURANCE GROUP, LTD annual and quarterly report in the SEC record with the published financial measures it tagged, 65 filings, each linked to its SEC index.

Filings with published measures

Each page shows what one filing reported, as tagged in that filing, with the periods it covered. Later filings can restate a value; the company overview shows the latest-filed value per period.

FormFiledFiscal periodMeasuresFactsSEC accession
10-Q2026-08-06fiscal Q2 2026321020001628280-26-053932
10-Q2026-05-06fiscal Q1 202632700001628280-26-030935
10-K2026-02-27fiscal FY 202537990001628280-26-012603
10-Q2025-11-06fiscal Q3 2025321020001628280-25-049910
10-Q2025-08-07fiscal Q2 2025321020000776867-25-000014
10-Q2025-05-07fiscal Q1 202532700000776867-25-000006
10-K2025-02-28fiscal FY 202436960000776867-25-000003
10-Q2024-11-06fiscal Q3 2024321020000776867-24-000019
10-Q2024-08-07fiscal Q2 2024321020000776867-24-000015
10-Q2024-05-09fiscal Q1 202432700000776867-24-000010
10-K2024-02-26fiscal FY 202337980000776867-24-000005
10-Q2023-11-06fiscal Q3 2023331040000776867-23-000017
10-Q2023-08-07fiscal Q2 202330860000776867-23-000013
10-Q2023-05-09fiscal Q1 202330620000776867-23-000006
10-K2023-02-27fiscal FY 202233880000776867-23-000004
10-Q2022-11-07fiscal Q3 202234960000776867-22-000016
10-Q2022-08-08fiscal Q2 202234960000776867-22-000013
10-Q2022-05-06fiscal Q1 202234700000776867-22-000005
10-K2022-02-28fiscal FY 202134890000776867-22-000002
10-Q2021-11-08fiscal Q3 202135980000776867-21-000021
10-Q2021-08-06fiscal Q2 202134920000776867-21-000016
10-Q2021-05-10fiscal Q1 202134700000776867-21-000008
10-K2021-02-26fiscal FY 2020331260000776867-21-000004
10-Q2020-11-06fiscal Q3 202033980000776867-20-000036
10-Q2020-08-07fiscal Q2 201930820000776867-20-000031
10-Q2020-05-08fiscal Q3 201929600000776867-20-000016
10-K2020-03-02fiscal FY 2019331240000776867-20-000009
10-Q2019-11-06fiscal Q3 201928770000776867-19-000030
10-Q2019-08-06fiscal Q2 201928780000776867-19-000024
10-Q2019-05-06fiscal Q1 201927540000776867-19-000015
10-K2019-02-27fiscal FY 2018311240000776867-19-000008
10-Q2018-11-05fiscal Q3 201827780000776867-18-000023
10-Q2018-08-07fiscal Q2 201827820000776867-18-000018
10-Q2018-05-02fiscal Q1 201826610000776867-18-000006
10-K2018-02-28fiscal FY 2017331260000776867-18-000002
10-Q2017-11-08fiscal Q3 201728840000776867-17-000037
10-Q2017-08-04fiscal Q2 201728840000776867-17-000029
10-Q2017-05-02fiscal Q1 201728620000776867-17-000012
10-K2017-02-27fiscal FY 2016321270000776867-17-000005
10-Q2016-11-02fiscal Q3 201629860000776867-16-000057
10-Q2016-08-03fiscal Q2 201629900000776867-16-000052
10-Q2016-05-02fiscal Q1 201628620000776867-16-000044
10-K2016-02-29fiscal FY 2015311240000776867-16-000036
10-Q2015-11-02fiscal Q3 201528880000776867-15-000030
10-Q2015-08-03fiscal Q2 201528880000776867-15-000024
10-Q2015-05-04fiscal Q1 201528640000776867-15-000012
10-K2015-02-27fiscal FY 2014311240000776867-15-000007
10-Q2014-10-29fiscal Q3 201425720001445305-14-004552
10-Q2014-07-29fiscal Q2 201424700001445305-14-002928
10-Q2014-04-28fiscal Q1 201424500001445305-14-001477
10-K2014-02-28fiscal FY 2013271140001445305-14-000693
10-Q2013-10-28fiscal Q3 201324700001445305-13-002529
10-Q2013-07-30fiscal Q2 201324700001445305-13-001733
10-Q2013-04-29fiscal Q1 201323480001445305-13-000949
10-K2013-03-01fiscal FY 2012271140001445305-13-000401
10-Q2012-10-30fiscal Q3 201224700001445305-12-003293
10-Q2012-07-27fiscal Q2 201224700001445305-12-002306
10-Q2012-04-27fiscal Q1 201223480001104659-12-029417
10-K2012-02-28fiscal FY 2011271130001104659-12-014041
10-Q2011-10-28fiscal Q3 201124700001104659-11-058632
10-Q2011-07-29fiscal Q2 201124700001104659-11-041664
10-Q2011-04-29fiscal Q1 201122450001104659-11-023962
10-K2011-02-28fiscal FY 201022600001104659-11-010544
10-Q2010-10-29fiscal Q3 201022610001104659-10-054516
10-Q2010-07-30fiscal Q2 201023630001104659-10-040660

Inspect the source

Entity
WHITE MOUNTAINS INSURANCE GROUP, LTD / CIK 0000776867
Captured
2026-09-19T15:03:25.512Z
SEC response SHA-256
074d84723b4e2b3ccc7778dbc5ffb7a461c3cd5f66bffa3f3afc35aad6657cec

Current SEC company facts · Download the original response snapshot (gzip) · Download the selected JSON

Every published concept a filing tagged, with the periods it covered, as reported in that filing at capture time. Forms 10-K, 10-K/A, 10-Q, 10-Q/A, 20-F, 20-F/A, 40-F, 40-F/A. A filing page needs at least 8 published concepts. Later filings can restate these values; the company history pages show the latest-filed value per period.

Public company accounting reference, not market prices, returns, an investment recommendation, or ALPHAC performance. Validate a separately constructed return series with the validation API; accounting values are not returns.

Use this in research

A financial period ends before its results become public. Use the filing date as a minimum availability boundary, inspect amendments, and retain the original filing vintage when testing historical signals. This latest-filed selection can contain information unavailable at the time.

These pages do not supply prices, total-return histories, corporate-action adjustments or a tradable universe. Build those inputs separately before evaluating a strategy. A profitable backtest can still reflect selection bias or costs that were left out.

Research methodology · Execution and cost assumptions · Check backtest overfitting

Build with the open-source tools

Use these accounting records as inspectable inputs. When you have constructed a return series, the validation tools can help test its statistical evidence and preserve the result with its limitations.

Read the published dataset with Python
import json
from urllib.request import urlopen

with urlopen("https://canlicapital.com/company-data/0000776867.json") as response:
    record = json.load(response)
print(record["fetched_at"])
print(record["policy"])
for concept in record["concepts"]:
    print(concept["tag"], next(iter(concept["observations"])))