UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the period ended June 30, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-8993 WHITE MOUNTAINS INSURANCE GROUP, LTD. (Exact name of Registrant as specified in its charter) Bermuda (State or other jurisdiction of incorporation ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the period ended March 31, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-8993 WHITE MOUNTAINS INSURANCE GROUP, LTD. (Exact name of Registrant as specified in its charter) Bermuda (State or other jurisdiction of incorporation ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2021 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-8993 WHITE MOUNTAINS INSURANCE GROUP, LTD. (Exact name of Registrant as specified in its charter) | Bermuda | 94-2708455 | | --- | --- | | (State ...

PART I. FINANCIAL INFORMATION [Financial Statements](index=3&type=section&id=Item%201.%20Financial%20Statements) White Mountains reported a **$361.9 million** net loss for the nine months ended September 30, 2021, primarily due to unrealized investment losses from MediaAlpha Consolidated Balance Sheet Summary (in millions) | Balance Sheet Item | September 30, 2021 | December 31, 2020 | | :--- | :--- | :--- | | **Total Investments** | $4,203.9 | $2,939.1 | | **Total Assets** | $7,113.6 | $4,831.4 | | **Total Liabilities** | $3,459.3 | $1,013.5 | | **Total Equity** | $3,654.3 | $3,817.9 | Consolidated Statement of Operations Summary (in millions) | Income Statement Item | Nine Months Ended Sep 30, 2021 | Nine Months Ended Sep 30, 2020 | | :--- | :--- | :--- | | **Total Revenues** | $594.8 | $659.9 | | **Total Expenses** | $933.5 | $372.0 | | **Pre-tax (Loss) Income** | $(338.7) | $287.9 | | **Net (Loss) Income** | $(361.9) | $190.0 | | **Net (Loss) Income Attributable to White Mountains** | $(308.2) | $219.5 | Consolidated Earnings Per Share (Loss) | EPS Metric | Nine Months Ended Sep 30, 2021 | Nine Months Ended Sep 30, 2020 | | :--- | :--- | :--- | | **Basic (Loss) Earnings Per Share** | $(99.45) | $70.14 | | **Diluted (Loss) Earnings Per Share** | $(99.45) | $70.14 | Consolidated Cash Flow Summary (in millions) | Cash Flow Item | Nine Months Ended Sep 30, 2021 | Nine Months Ended Sep 30, 2020 | | :--- | :--- | :--- | | **Net Cash from Operations** | $46.0 | $12.2 | | **Net Cash (Used to) Provided from Investing** | $(169.4) | $28.0 | | **Net Cash from Financing** | $222.3 | $13.8 | | **Net Change in Cash** | $99.5 | $53.8 | [Management's Discussion and Analysis of Financial Condition and Results of Operations](index=56&type=section&id=Item%202.%20Management's%20Discussion%20and%20Analysis%20of%20Financial%20Condition%20and%20Results%20of%20Operations) Book value per share decreased **9%** in Q3 2021 and **8%** year-to-date, primarily due to a **$397 million** unrealized loss from MediaAlpha - Book value per share was **$1,162** as of September 30, 2021, a decrease of **9%** in the third quarter and **8%** year-to-date, driven by net realized and unrealized investment losses of **$326 million** from MediaAlpha, whose share price fell from **$39.07** at year-end 2020 to **$18.68** at the end of Q3 2021[248](index=248&type=chunk)[249](index=249&type=chunk) - Excluding MediaAlpha, operating segments showed solid performance: Ark reported a Q3 adjusted combined ratio of **89%**, NSM's adjusted EBITDA grew **24%** year-over-year to **$19 million**, and Kudu deployed **$131 million** in new investments[250](index=250&type=chunk)[253](index=253&type=chunk)[254](index=254&type=chunk)[255](index=255&type=chunk) Book Value Per Share Reconciliation | Metric | September 30, 2021 | December 31, 2020 | | :--- | :--- | :--- | | **GAAP Book Value Per Share** | $1,162.44 | $1,259.18 | | **Adjusted Book Value Per Share** | $1,175.86 | $1,263.64 | [Results of Operations](index=56&type=section&id=Results%20of%20Operations) Consolidated pre-tax loss for Q3 2021 was **$362.3 million**, a reversal from Q3 2020 income, primarily due to a **$396.8 million** unrealized loss on the MediaAlpha investment in Other Operations Pre-tax Income (Loss) by Segment (in millions) | Segment | Q3 2021 | Q3 2020 | YTD 2021 | YTD 2020 | | :--- | :--- | :--- | :--- | :--- | | Financial Guarantee (HG Global/BAM) | $(8.0) | $(1.1) | $(31.1) | $11.3 | | P&C Insurance (Ark) | $10.9 | — | $(3.8) | — | | Specialty Insurance Distribution (NSM) | $(1.6) | $(1.2) | $(33.8) | $(6.3) | | Asset Management (Kudu) | $23.3 | $12.6 | $70.4 | $8.9 | | Other Operations | $(386.9) | $310.9 | $(340.4) | $274.0 | | **Total Pre-tax (Loss) Income** | **$(362.3)** | **$321.2** | **$(338.7)** | **$287.9** | - The Ark segment, acquired in January 2021, reported a Q3 GAAP combined ratio of **92%** and an adjusted combined ratio of **89%**, including **21 points** of catastrophe losses offset by **6 points** of favorable prior year reserve development[290](index=290&type=chunk)[291](index=291&type=chunk)[292](index=292&type=chunk) - The NSM segment's Q3 adjusted EBITDA increased to **$19.1 million** from **$15.4 million** in Q3 2020, driven by growth in Pet and Social Services verticals, with a YTD pre-tax loss of **$33.8 million** including a **$28.7 million** loss on the Fresh Insurance motor business sale[306](index=306&type=chunk)[307](index=307&type=chunk)[308](index=308&type=chunk) - The Kudu segment's Q3 pre-tax income grew to **$23.3 million** from **$12.6 million** year-over-year, largely due to **$18.9 million** in unrealized investment gains on participation contracts and increased investment income from new deployments[324](index=324&type=chunk)[325](index=325&type=chunk) [Liquidity and Capital Resources](index=82&type=section&id=Liquidity%20and%20Capital%20Resources) The company maintains adequate liquidity with **$507 million** in net unrestricted cash and liquid investments, while total debt increased to **$710.4 million**, raising the debt-to-adjusted capital ratio to **15.7%** - Management believes cash balances and operating cash flows are adequate to meet expected cash requirements for the foreseeable future at both holding company and subsidiary levels[364](index=364&type=chunk) Capital Structure (in millions) | Component | September 30, 2021 | December 31, 2020 | | :--- | :--- | :--- | | Total Debt | $710.4 | $376.4 | | Total White Mountains's common shareholders' equity | $3,521.7 | $3,906.0 | | **Total Adjusted Capital** | **$4,510.7** | **$4,312.7** | | **Total Debt to Total Adjusted Capital** | **15.7%** | **8.7%** | - In Q3 2021, the company repurchased **79,294** common shares for **$87 million** at an average price of **$1,099** per share, with **86,512** shares repurchased for **$95 million** year-to-date[382](index=382&type=chunk) [Non-GAAP Financial Measures](index=87&type=section&id=Non-GAAP%20Financial%20Measures) The company uses non-GAAP measures like adjusted book value per share, adjusted combined ratio, and adjusted EBITDA to provide a clearer view of intrinsic value and underlying segment performance - Adjusted book value per share is calculated by adjusting GAAP book value for the time value of money on BAM Surplus Notes and the unearned premium reserve at HG Global[397](index=397&type=chunk)[398](index=398&type=chunk) - Ark's adjusted combined ratio adds back amounts ceded to third-party capital providers to evaluate results on a fully aligned basis[403](index=403&type=chunk) - NSM's and Kudu's adjusted EBITDA measures exclude items such as changes in contingent consideration, non-cash compensation, acquisition expenses, and unrealized investment gains to better reflect core operational profitability[405](index=405&type=chunk)[407](index=407&type=chunk) [Critical Accounting Estimates](index=89&type=section&id=Critical%20Accounting%20Estimates) Critical accounting estimates focus on fair value measurements for investments and liabilities, with a substantial portion relying on unobservable inputs (Level 3) requiring significant management judgment - As of September 30, 2021, **69%** of the investment portfolio was priced using observable inputs (Level 1 or 2), with the remainder relying on unobservable inputs (Level 3) or Net Asset Value as a practical expedient[414](index=414&type=chunk) - The fair value of Kudu's Participation Contracts (**$605 million**) is determined using discounted cash flow models with key unobservable inputs including pre-tax discount rates (**18%-23%**) and terminal cash flow exit multiples (**7x-13x**)[424](index=424&type=chunk)[425](index=425&type=chunk) - The fair value of the investment in PassportCard/DavidShield (**$105 million**) is determined via a discounted cash flow model, using an after-tax discount rate of **23%** and a terminal revenue growth rate of **4%**[427](index=427&type=chunk)[429](index=429&type=chunk) [Quantitative and Qualitative Disclosures About Market Risk](index=93&type=section&id=Item%203.%20Quantitative%20and%20Qualitative%20Disclosures%20About%20Market%20Risk) The company refers to its 2020 Annual Report on Form 10-K for market risk disclosures, indicating no material changes during the quarter - The report refers to the company's 2020 Form 10-K for quantitative and qualitative disclosures about market risk, implying no material updates for the current reporting period[437](index=437&type=chunk) [Controls and Procedures](index=94&type=section&id=Item%204.%20Controls%20and%20Procedures) Disclosure controls and procedures were effective as of the reporting period, with no significant changes to internal control over financial reporting during the quarter - The PEO and PFO have evaluated and concluded that the company's disclosure controls and procedures are effective as of September 30, 2021[438](index=438&type=chunk) - No significant changes were made to the company's internal control over financial reporting during the third quarter of 2021[439](index=439&type=chunk) PART II. OTHER INFORMATION [Legal Proceedings](index=94&type=section&id=Item%201.%20Legal%20Proceedings) The company reported no new legal proceedings for the period - There are no legal proceedings to report for the quarter[440](index=440&type=chunk) [Risk Factors](index=94&type=section&id=Item%201A.%20Risk%20Factors) No material changes to the risk factors previously disclosed in the company's 2020 Annual Report on Form 10-K were reported - No material changes to risk factors from the 2020 Form 10-K were reported[441](index=441&type=chunk) [Issuer Purchases of Equity Securities](index=94&type=section&id=Item%202.%20Issuer%20Purchases%20of%20Equity%20Securities) During Q3 2021, the company repurchased **79,351** common shares for **$1,098.82** average price per share, with **463,223** shares remaining authorized for repurchase Share Repurchases for Q3 2021 | Month | Total Shares Purchased | Average Price Paid per Share | | :--- | :--- | :--- | | July 2021 | 2,841 | $1,122.87 | | August 2021 | 16,878 | $1,123.41 | | September 2021 | 59,632 | $1,090.72 | | **Total** | **79,351** | **$1,098.82** | - As of the end of the quarter, the company has authorization to repurchase an additional **463,223** common shares[442](index=442&type=chunk)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the period ended June 30, 2021 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-8993 WHITE MOUNTAINS INSURANCE GROUP, LTD. (Exact name of Registrant as specified in its charter) Bermuda (State or other jurisdiction of incorporation ...

PART I. FINANCIAL INFORMATION This section presents the company's unaudited financial statements, management's analysis of financial condition and operations, market risk disclosures, and internal controls [Item 1. Financial Statements (Unaudited)](index=3&type=section&id=Item%201.%20Financial%20Statements%20%28Unaudited%29) The unaudited consolidated financial statements for Q1 2021 reflect increased assets due to the Ark acquisition and a reduced net loss, impacted by investment losses and transaction costs Consolidated Balance Sheet Summary (in millions) | Balance Sheet Item | March 31, 2021 | December 31, 2020 | | :--- | :--- | :--- | | **Total Assets** | **$6,900.7** | **$4,831.4** | | Total P&C Insurance and Reinsurance (Ark) assets | $2,840.2 | $— | | **Total Liabilities** | **$2,964.8** | **$1,013.5** | | Total P&C Insurance and Reinsurance (Ark) liabilities | $2,006.8 | $— | | **Total Equity** | **$3,935.9** | **$3,817.9** | | White Mountains's common shareholders' equity | $3,825.9 | $3,906.0 | Consolidated Statement of Operations Summary (in millions) | Income Statement Item | Three Months Ended March 31, 2021 | Three Months Ended March 31, 2020 | | :--- | :--- | :--- | | **Total Revenues** | **$178.2** | **$(59.2)** | | P&C Insurance and Reinsurance (Ark) revenues | $109.1 | $— | | Net realized/unrealized investment (losses) gains from MediaAlpha | $(41.7) | $30.0 | | **Total Expenses** | **$316.9** | **$106.8** | | P&C Insurance and Reinsurance (Ark) expenses | $141.6 | $— | | **Net Loss Attributable to White Mountains's Common Shareholders** | **$(75.3)** | **$(128.8)** | Earnings Per Share (EPS) Summary | EPS Item | Three Months Ended March 31, 2021 | Three Months Ended March 31, 2020 | | :--- | :--- | :--- | | Basic (loss) per share - Continuing operations | $(30.33) | $(40.82) | | Basic earnings per share - Discontinued operations | $6.03 | $0.28 | | **Total consolidated basic (loss) per share** | **$(24.30)** | **$(40.54)** | [Notes to Consolidated Financial Statements](index=10&type=section&id=Notes%20to%20Consolidated%20Financial%20Statements) These notes detail significant accounting policies and transactions, including the Ark acquisition, MediaAlpha share offering, and new accounting standard adoptions, highlighting their financial impact - On January 1, 2021, White Mountains completed its acquisition of Ark, contributing **$605.4 million** in equity capital and purchasing **$40.9 million** in shares, resulting in the recognition of **$2.5 billion** in assets and **$1.7 billion** in liabilities, including **$292.5 million** in goodwill and other intangibles[58](index=58&type=chunk)[59](index=59&type=chunk)[60](index=60&type=chunk) - In a secondary offering on March 23, 2021, White Mountains sold **3.6 million** MediaAlpha shares for net proceeds of **$160.3 million**, reducing its ownership to **28.5%**, with the fair value of the remaining stake at **$600.2 million** at quarter-end[57](index=57&type=chunk) - NSM sold its Fresh Insurance motor business on April 12, 2021, with assets classified as held for sale as of March 31, 2021, resulting in a recognized loss of **$28.7 million** in Q1 2021[68](index=68&type=chunk) - As of March 31, 2021, the company's reportable segments are HG Global/BAM, Ark, NSM, Kudu, and Other Operations, with Ark being a new segment following the acquisition[30](index=30&type=chunk) [Management's Discussion and Analysis of Financial Condition and Results of Operations](index=53&type=section&id=Item%202.%20Management%27s%20Discussion%20and%20Analysis%20of%20Financial%20Condition%20and%20Results%20of%20Operations) Management attributes a **2%** decrease in adjusted book value per share to MediaAlpha's stock decline, Ark acquisition costs, and an NSM asset sale loss, while detailing segment performance and liquidity - Book value per share and adjusted book value per share decreased by **2%** in Q1 2021, primarily driven by a decrease in the market price of the company's investment in MediaAlpha, a loss on assets held for sale for NSM's Fresh Insurance motor business, and transaction expenses at Ark[229](index=229&type=chunk) Adjusted Book Value Per Share | Metric | March 31, 2021 | December 31, 2020 | | :--- | :--- | :--- | | GAAP book value per share | $1,231.27 | $1,259.18 | | Adjusted book value per share (Non-GAAP) | $1,241.71 | $1,263.64 | - The total investment portfolio returned **-0.3%** in Q1 2021, but excluding the investment in MediaAlpha, the portfolio returned **0.7%**, driven by favorable results in other long-term investments, partially offset by the impact of rising interest rates on the fixed income portfolio[235](index=235&type=chunk) [Results of Operations](index=53&type=section&id=Results%20of%20Operations%20for%20the%20Three%20Months%20Ended%20March%2031%2C%202021%20and%202020) Consolidated pre-tax loss improved to **$138.7 million**, with Ark contributing a **$32.5 million** loss, NSM's loss widening to **$33.3 million**, and Kudu achieving **$15.7 million** in pre-tax income Pre-tax (Loss) Income by Segment (in millions) | Segment | Q1 2021 | Q1 2020 | | :--- | :--- | :--- | | HG Global/BAM | $(25.0) | $1.1 | | P&C Insurance and Reinsurance (Ark) | $(32.5) | — | | Specialty Insurance Distribution (NSM) | $(33.3) | $(1.4) | | Asset Management (Kudu) | $15.7 | $(21.4) | | Other Operations | $(63.6) | $(144.3) | | **Total Pre-tax Loss** | **$(138.7)** | **$(166.0)** | - Ark reported a GAAP combined ratio of **109%** and an adjusted combined ratio of **108%**, including **17 points** of catastrophe losses, with **14 points** related to Winter Storm Uri[232](index=232&type=chunk)[264](index=264&type=chunk) - NSM's adjusted EBITDA grew to **$14.4 million** from **$10.5 million** year-over-year, driven by the acquisition of Kingsbridge and organic growth in the pet and social services verticals[233](index=233&type=chunk)[273](index=273&type=chunk)[274](index=274&type=chunk) - Kudu's pre-tax income of **$16 million** was driven by **$16 million** in unrealized gains on its Participation Contracts, and Kudu deployed an additional **$11 million** in an existing portfolio company during the quarter[234](index=234&type=chunk)[284](index=284&type=chunk) [Liquidity and Capital Resources](index=73&type=section&id=Liquidity%20and%20Capital%20Resources) The company maintains strong liquidity with **$600 million** in unrestricted cash and investments, a **9.5%** debt-to-adjusted-capital ratio, and key financing activities including Kudu's new **$300 million** credit facility - At the holding company level, White Mountains had **$600 million** of net unrestricted cash, short-term investments, and fixed maturity investments, in addition to its **$600 million** stake in MediaAlpha and other private equity funds[324](index=324&type=chunk)[344](index=344&type=chunk) Capital Structure (in millions) | Component | March 31, 2021 | December 31, 2020 | | :--- | :--- | :--- | | Total debt | $429.7 | $376.4 | | Total White Mountains's common shareholders' equity | $3,825.9 | $3,906.0 | | Total adjusted capital (Non-GAAP) | $4,501.9 | $4,312.7 | | **Total debt to total adjusted capital** | **9.5%** | **8.7%** | - Kudu replaced its existing bank facility with a new secured revolving credit facility with a maximum capacity of **$300 million**, maturing in 2036, with an initial draw of **$102 million**[336](index=336&type=chunk) - During Q1 2021, White Mountains repurchased **7,161** common shares for **$7 million**, primarily to satisfy employee tax withholding obligations[342](index=342&type=chunk) [Non-GAAP Financial Measures](index=79&type=section&id=Non-GAAP%20Financial%20Measures) The company uses non-GAAP measures like adjusted book value per share, adjusted EBITDA for NSM and Kudu, and adjusted combined ratio for Ark to provide deeper insights into financial performance - Adjusted book value per share is used to analyze the intrinsic value of HG Global, including the value of BAM Surplus Notes and in-force business at HG Re[354](index=354&type=chunk)[357](index=357&type=chunk) - Ark's adjusted combined ratio adds back amounts ceded to TPC Providers to evaluate results on a fully aligned basis, as these arrangements relate to periods before the White Mountains transaction[360](index=360&type=chunk) - NSM's and Kudu's adjusted EBITDA measures exclude items like changes in fair value of contingent consideration, non-cash compensation, acquisition costs, and restructuring expenses to better reflect core operating performance[361](index=361&type=chunk)[364](index=364&type=chunk) [Critical Accounting Estimates](index=81&type=section&id=Critical%20Accounting%20Estimates) Critical accounting estimates primarily involve fair value measurements for Level 3 assets, which constitute **27%** of the investment portfolio and rely on significant management judgment and valuation models - Approximately **73%** of the investment portfolio was priced using Level 1 or Level 2 inputs (quoted market prices or other observable data)[372](index=372&type=chunk) - Level 3 investments, valued using unobservable inputs, include Kudu's Participation Contracts and the investment in PassportCard/DavidShield, with their valuation relying on discounted cash flow models and significant management judgment on inputs like discount rates and growth projections[380](index=380&type=chunk)[381](index=381&type=chunk)[382](index=382&type=chunk) Valuation Sensitivity for Kudu's Participation Contracts (in millions) | Scenario | Estimated Fair Value | | :--- | :--- | | **Base Case (18%-23% discount rate, 7x-12x exit multiple)** | **$427** | | +2% discount rate | $385 | | -2% discount rate | $476 | | +2x exit multiple | $456 | | -2x exit multiple | $400 | [Forward-Looking Statements](index=85&type=section&id=Forward-Looking%20Statements) This section cautions that forward-looking statements on business strategy and financial targets are subject to risks including catastrophic events, loss reserves, MediaAlpha's value, and COVID-19 impacts - The company identifies forward-looking statements related to its business strategy, financial targets, loss reserves, and growth projections[394](index=394&type=chunk) - Key risks that could cause actual results to differ from projections include catastrophic events, inadequate loss reserves, the market value of its MediaAlpha investment, COVID-19 uncertainties, and rating agency actions[397](index=397&type=chunk) [Quantitative and Qualitative Disclosures About Market Risk](index=85&type=section&id=Item%203.%20Quantitative%20and%20Qualitative%20Disclosures%20About%20Market%20Risk) This section refers to the 2020 Annual Report on Form 10-K for market risk disclosures, indicating no material changes - The report references the 2020 Annual Report on Form 10-K for quantitative and qualitative disclosures about market risk, implying no material updates for the current quarter[397](index=397&type=chunk) [Controls and Procedures](index=86&type=section&id=Item%204.%20Controls%20and%20Procedures) Management concluded that disclosure controls and procedures were effective as of March 31, 2021, with no significant changes to internal control over financial reporting - Management concluded that the company's disclosure controls and procedures are effective as of March 31, 2021[398](index=398&type=chunk) - There were no significant changes in internal control over financial reporting during the first quarter of 2021[399](index=399&type=chunk) PART II. OTHER INFORMATION This section covers other information including legal proceedings, risk factors, defaults, equity security repurchases, and exhibits [Other Information Items](index=86&type=section&id=Items%201%20through%206.) The company reported no new material legal proceedings or risk factor changes, detailed the repurchase of **7,161** shares for **$7.2 million**, and listed filed exhibits - The company reported no new material legal proceedings or material changes to its risk factors since the 2020 Annual Report on Form 10-K[400](index=400&type=chunk)[401](index=401&type=chunk) Issuer Purchases of Equity Securities (Q1 2021) | Month | Total Shares Purchased | Average Price Paid per Share | | :--- | :--- | :--- | | January 2021 | 5,418 | $1,000.66 | | February 2021 | 181 | $1,096.81 | | March 2021 | 1,562 | $1,165.12 | | **Total** | **7,161** | **$1,038.96** | - As of March 31, 2021, the company has authorization to repurchase an additional **542,517** common shares[402](index=402&type=chunk)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2020 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-8993 WHITE MOUNTAINS INSURANCE GROUP, LTD. (Exact name of Registrant as specified in its charter) Bermuda 94-2708455 (State or other jurisdiction ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the period ended September 30, 2020 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-8993 WHITE MOUNTAINS INSURANCE GROUP, LTD. (Exact name of Registrant as specified in its charter) | Bermuda | | | --- | --- | | (State or other jur ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the period ended June 30, 2020 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-8993 WHITE MOUNTAINS INSURANCE GROUP, LTD. (Exact name of Registrant as specified in its charter) | Bermuda | | | --- | --- | | (State or other jurisdic ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the period ended March 31, 2020 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-8993 WHITE MOUNTAINS INSURANCE GROUP, LTD. (Exact name of Registrant as specified in its charter) | Bermuda | | --- | (State or other jurisdiction of i ...