v3.25.2
Investment Securities (Tables)
6 Months Ended
Jun. 30, 2025
Investments, Debt and Equity Securities [Abstract]  
Schedule of pre-tax net investment income
The following table presents pre-tax net investment income for the three and six months ended June 30, 2025 and 2024:
Three Months Ended June 30,Six Months Ended June 30,
Millions2025202420252024
Fixed maturity investments$26.8 $23.2 $53.8 $43.9 
Short-term investments12.0 16.0 22.6 32.0 
Common equity securities.2 .6 .6 1.1 
Other long-term investments23.1 18.4 45.3 38.9 
Total investment income62.1 58.2 122.3 115.9 
Third-party investment expenses(.7)(.8)(1.3)(1.5)
Net investment income, pre-tax$61.4 $57.4 $121.0 $114.4 
Schedule of net realized and unrealized investment gains and losses
The following table presents net realized and unrealized investment gains (losses) for the three and six months ended June 30, 2025 and 2024:
Three Months Ended June 30,Six Months Ended June 30,
Millions2025202420252024
Realized investment gains (losses)
Fixed maturity investments$(1.8)$(2.9)$(1.9)$(8.7)
Short-term investments.3 (.1).5 (.3)
Common equity securities33.1 3.5 67.7 3.5 
Investment in MediaAlpha  91.2  91.2 
Other long-term investments6.2 29.2 11.8 29.5 
Net realized investment gains (losses)37.8 120.9 78.1 115.2 
Unrealized investment gains (losses)
Fixed maturity investments17.2 .3 39.4 (7.2)
Short-term investments.5 (.1).5 (1.1)
Common equity securities(9.5)15.8 (31.6)38.9 
Investment in MediaAlpha30.5 (230.4)(6.1)(19.7)
Other long-term investments40.8 33.3 87.0 40.5 
Net unrealized investment gains (losses)79.5 (181.1)89.2 51.4 
Net realized and unrealized investment gains (losses) (1)
$117.3 $(60.2)$167.3 $166.6 
Fixed maturity and short-term investments
   Net realized and unrealized investment gains (losses)$16.2 $(2.8)$38.5 $(17.3)
Less: net realized and unrealized gains (losses) on investment
   securities sold during the period
(.6).3 1.1 (.3)
Net unrealized investment gains (losses) recognized during the period on
   investment securities held at the end of the period
$16.8 $(3.1)$37.4 $(17.0)
Common equity securities and investment in MediaAlpha
Net realized and unrealized investment gains (losses) on common
   equity securities
$23.6 $19.3 $36.1 $42.4 
Net realized and unrealized investment gains (losses) from
    investment in MediaAlpha
30.5 (139.2)(6.1)71.5 
Total net realized and unrealized investment gains (losses) 54.1 (119.9)30.0 113.9 
Less: net realized and unrealized gains (losses) on investment
   securities sold during the period
9.4 (11.0)6.4 35.4 
Net unrealized investment gains (losses) recognized during the period on
   investment securities held at the end of the period
$44.7 $(108.9)$23.6 $78.5 
(1) For the three months ended June 30, 2025 and 2024, includes $30.1 and $(0.3) of net realized and unrealized investment gains (losses) related to foreign currency exchange. For the six months ended June 30, 2025 and 2024, includes $37.3 and $(11.8) of net realized and unrealized investment gains (losses) related to foreign currency exchange.

The following table presents total net unrealized gains (losses) attributable to Level 3 investments for the three and six months ended June 30, 2025 and 2024 for investments still held at the end of the period:
Three Months Ended June 30,Six Months Ended June 30,
Millions2025202420252024
Total net unrealized investment gains on other long-term investments held at the end of period, pre-tax$18.4 $57.5 $63.4 $51.3 
Schedule of equity securities and other long-term investments
The following tables present the cost or amortized cost, gross unrealized investment gains (losses), net foreign currency gains (losses) and carrying value of White Mountains’s fixed maturity investments as of June 30, 2025 and December 31, 2024:
 June 30, 2025
MillionsCost or
Amortized
Cost
Gross
Unrealized
Gains
Gross
Unrealized
Losses
Net Foreign
Currency Gains (Losses)
Carrying
Value
U.S. Government and agency obligations$480.8 $2.0 $(.3)$ $482.5 
Debt securities issued by corporations1,419.4 11.1 (17.0)(.3)1,413.2 
Municipal obligations3.2    3.2 
Mortgage and asset-backed securities421.9 1.5 (20.9) 402.5 
Collateralized loan obligations303.0 .9 (.1)3.0 306.8 
Foreign government and agency obligations26.0 .2  1.5 27.7 
Total fixed maturity investments $2,654.3 $15.7 $(38.3)$4.2 $2,635.9 

 December 31, 2024
MillionsCost or
Amortized
Cost
Gross
Unrealized
Gains
Gross
Unrealized
Losses
Net Foreign
Currency
Gains (Losses)
Carrying
Value
U.S. Government and agency obligations$461.8 $1.1 $(.8)$— $462.1 
Debt securities issued by corporations1,444.5 4.6 (31.4)(3.5)1,414.2 
Municipal obligations3.2 — — — 3.2 
Mortgage and asset-backed securities400.2 .2 (26.5)— 373.9 
Collateralized loan obligations237.3 1.2 (.2)(1.6)236.7 
Foreign government and agency obligations22.2 — (.1)(.6)21.5 
Total fixed maturity investments $2,569.2 $7.1 $(59.0)$(5.7)$2,511.6 
The following tables present the cost or amortized cost, gross unrealized investment gains (losses), net foreign currency gains (losses) and carrying value of common equity securities, White Mountains’s investment in MediaAlpha and other long-term investments as of June 30, 2025 and December 31, 2024:
 June 30, 2025
MillionsCost or
Amortized
Cost
Gross
Unrealized
Gains
Gross
Unrealized
Losses
Net Foreign
Currency Gains (Losses)
Carrying
Value
Common equity securities$353.7 $81.3 $ $ $435.0 
Investment in MediaAlpha$59.2 $136.3 $ $ $195.5 
Other long-term investments$1,818.5 $624.3 $(126.0)$(9.7)$2,307.1 

 December 31, 2024
MillionsCost or
Amortized
Cost
Gross
Unrealized
Gains
Gross
Unrealized
Losses
Net Foreign
Currency
Gains (Losses)
Carrying
Value
Common equity securities$537.0 $120.4 $— $(7.4)$650.0 
Investment in MediaAlpha$59.2 $142.4 $— $— $201.6 
Other long-term investments$1,748.7 $546.4 $(116.7)$(28.2)$2,150.2 
Schedule of contractual maturities of fixed maturities
The following table presents the cost or amortized cost and carrying value of White Mountains’s fixed maturity investments by contractual maturity as of June 30, 2025 and December 31, 2024. Actual maturities could differ from contractual maturities because borrowers may have the right to call or prepay certain obligations with or without penalties.
June 30, 2025December 31, 2024
MillionsCost or Amortized CostCarrying ValueCost or Amortized CostCarrying Value
Due in one year or less$399.9 $398.2 $205.8 $203.9 
Due after one year through five years1,370.0 1,371.4 1,494.5 1,478.7 
Due after five years through ten years149.7 147.1 206.1 193.2 
Due after ten years9.8 9.9 25.3 25.2 
Mortgage and asset-backed securities and
   collateralized loan obligations
724.9 709.3 637.5 610.6 
Total fixed maturity investments$2,654.3 $2,635.9 $2,569.2 $2,511.6 
Schedule of fair value measurements for investment securities by level
The following tables present White Mountains’s fair value measurements for investments as of June 30, 2025 and December 31, 2024 by level. The major security types were based on the legal form of the securities. White Mountains has disaggregated its fixed maturity investments based on the issuing entity type, which impacts credit quality, with debt securities issued by U.S. government entities carrying minimal credit risk, while the credit and other risks associated with other issuers, such as corporations, foreign governments and agencies, municipalities, entities issuing mortgage and asset-backed securities or entities issuing collateralized loan obligations vary depending on the nature of the issuing entity type. White Mountains further disaggregates debt securities issued by corporations by industry sector because investors often reference commonly used benchmarks and their subsectors to monitor risk and performance. Accordingly, White Mountains has further disaggregated this asset class into subclasses based on the similar sectors and industry classifications it uses to evaluate investment risk and performance against commonly used benchmarks, such as the Bloomberg U.S. Intermediate Aggregate Index.
 June 30, 2025
MillionsFair ValueLevel 1Level 2Level 3
Fixed maturity investments:    
U.S. Government and agency obligations$482.5 $481.7 $.8 $ 
Debt securities issued by corporations:
Financials494.4  494.4  
Consumer270.3  270.3  
Industrial160.3  160.3  
Healthcare156.3  156.3  
Technology94.9  94.9  
Energy62.9  62.9  
Communications62.1  62.1  
Utilities56.7  56.7  
Materials55.3  55.3  
Total debt securities issued by corporations1,413.2  1,413.2  
Municipal obligations3.2  3.2  
Mortgage and asset-backed securities402.5  402.5  
Collateralized loan obligations306.8  306.8  
Foreign government and agency obligations27.7  27.7  
Total fixed maturity investments2,635.9 481.7 2,154.2  
Short-term investments1,225.1 1,193.6 31.5  
Common equity securities (1)
435.0  435.0  
Investment in MediaAlpha195.5 195.5   
Other long-term investments1,424.8  32.0 1,392.8 
Other long-term investments net asset value (2)
882.3    
Total other long-term investments2,307.1  32.0 1,392.8 
Total investments$6,798.6 $1,870.8 $2,652.7 $1,392.8 
(1) Consists of investments in listed funds that predominantly invest in international equities.
(2) Consists of private equity funds and hedge funds, a bank loan fund, Lloyd’s trust deposits and ILS funds for which fair value is measured using net asset value (“NAV”) as a practical expedient. Investments for which fair value is measured at NAV are not classified within the fair value hierarchy.
December 31, 2024
MillionsFair ValueLevel 1Level 2Level 3
Fixed maturity investments:    
U.S. Government and agency obligations$462.1 $461.3 $.8 $— 
Debt securities issued by corporations:
Financials466.7 — 466.7 — 
Consumer255.2 — 255.2 — 
Industrial164.4 — 164.4 — 
Healthcare153.1 — 153.1 — 
Technology113.8 — 113.8 — 
Energy62.8 — 62.8 — 
Communications71.6 — 71.6 — 
Utilities60.9 — 60.9 — 
Materials65.7 — 65.7 — 
Total debt securities issued by corporations1,414.2 — 1,414.2 — 
Municipal obligations3.2 — 3.2 — 
Mortgage and asset-backed securities373.9 — 373.9 — 
Collateralized loan obligations236.7 — 236.7 — 
Foreign government and agency obligations21.5 — 21.5 — 
Total fixed maturity investments2,511.6 461.3 2,050.3 — 
Short-term investments964.2 951.1 13.1 — 
Common equity securities:
Exchange-traded funds224.6 224.6 — — 
Other (1)
425.4 — 425.4 — 
Total common equity securities650.0 224.6 425.4 — 
Investment in MediaAlpha201.6 201.6 — — 
Other long-term investments1,286.2 — 23.5 1,262.7 
Other long-term investments NAV (2)
864.0 — — — 
Total other long-term investments2,150.2 — 23.5 1,262.7 
Total investments$6,477.6 $1,838.6 $2,512.3 $1,262.7 
(1) Consists of investments in listed funds that predominantly invest in international equities.
(2) Consists of private equity funds and hedge funds, a bank loan fund, Lloyd’s trust deposits and ILS funds for which fair value is measured using NAV as a practical expedient. Investments for which fair value is measured at NAV are not classified within the fair value hierarchy.
Schedule of credit ratings of debt securities issued
The following table presents the fair values for credit ratings of debt securities issued by corporations held in White Mountains’s investment portfolio as of June 30, 2025 and December 31, 2024:
Fair Value at
MillionsJune 30, 2025December 31, 2024
AAA$12.1 $14.6 
AA88.6 91.2 
A667.1 607.2 
BBB631.5 688.7 
BB5.8 5.4 
Other8.1 7.1 
Debt securities issued by corporations (1)
$1,413.2 $1,414.2 
(1)    Credit ratings are based upon issuer credit ratings provided by Standard & Poor’s Financial Services LLC (“Standard & Poor’s”), or if unrated by Standard & Poor’s, long-term obligation ratings provided by Moody’s Investor Service, Inc.
Schedule of mortgage and asset-backed securities
The following table presents the fair value of White Mountains’s mortgage and asset-backed securities and collateralized loan obligations as of June 30, 2025 and December 31, 2024:
 June 30, 2025December 31, 2024
MillionsFair ValueLevel 2Level 3Fair ValueLevel 2Level 3
Mortgage-backed securities:      
Agency:      
FNMA$200.9 $200.9 $ $198.3 $198.3 $— 
FHLMC144.1 144.1  147.1 147.1 — 
GNMA23.3 23.3  24.2 24.2 — 
   Total agency (1)
368.3 368.3  369.6 369.6 — 
Non-agency: Commercial.4 .4  .4 .4 — 
   Total non-agency.4 .4  .4 .4 — 
   Total mortgage-backed securities368.7 368.7  370.0 370.0 — 
Other asset-backed securities:
Vehicle receivables17.9 17.9  1.7 1.7 — 
Credit card receivables10.6 10.6  .2 .2 — 
Other5.3 5.3  2.0 2.0 — 
Total other asset-backed securities33.8 33.8  3.9 3.9 — 
Total mortgage and asset-backed securities402.5402.5 373.9373.9— 
Collateralized loan obligations306.8 306.8  236.7 236.7 — 
Total mortgage and asset-backed securities
   and collateralized loan obligations
$709.3 $709.3 $ $610.6 $610.6 $— 
(1)    Represents publicly traded mortgage-backed securities which carry the full faith and credit guaranty of the U.S. Government (i.e., GNMA) or are guaranteed by a government sponsored entity (i.e., FNMA, FHLMC).
Schedule of carrying values for other long-term investments
The following tables present the carrying values of White Mountains’s other long-term investments by reportable segment as of June 30, 2025 and December 31, 2024:
Fair Value as of June 30, 2025
MillionsArk/ WM OutriggerKuduOtherTotal
Kudu’s Participation Contracts $ $1,121.1 $ $1,121.1 
PassportCard/DavidShield
  155.0 155.0 
Elementum  35.0 35.0 
Other unconsolidated entities (1)
  77.2 77.2 
Total unconsolidated entities 1,121.1 267.2 1,388.3 
Private equity funds and hedge funds142.6  220.5 363.1 
Bank loan fund270.9   270.9 
Lloyd’s trust deposits 159.0   159.0 
ILS funds  73.6 73.6 
Private debt instruments 6.1 9.5 15.6 
Other36.6   36.6 
Total other long-term investments$609.1 $1,127.2 $570.8 $2,307.1 
(1) Includes White Mountains’s noncontrolling equity interests in certain preferred securities, private equity securities, limited liability company units and limited partnership units.
Fair Value as of December 31, 2024
MillionsArk/ WM OutriggerKuduOtherTotal
Kudu’s Participation Contracts $— $1,008.4 $— $1,008.4 
PassportCard/DavidShield
— — 150.0 150.0 
Elementum — — 35.0 35.0 
Other unconsolidated entities (1)
— — 63.6 63.6 
Total unconsolidated entities— 1,008.4 248.6 1,257.0 
Private equity funds and hedge funds104.1 — 256.5 360.6 
Bank loan fund264.7 — — 264.7 
Lloyd’s trust deposits 149.9 — — 149.9 
ILS funds— — 74.0 74.0 
Private debt instruments— 5.6 9.3 14.9 
Other29.1 — — 29.1 
Total other long-term investments$547.8 $1,014.0 $588.4 $2,150.2 
(1) Includes White Mountains’s noncontrolling equity interests in certain preferred securities, limited liability company units, limited partnership units and SAFE investments.
Schedule of investments and unfunded commitments by investment objective and sector
The following table presents the fair value of investments and unfunded commitments in private equity funds and hedge funds by investment objective and sector as of June 30, 2025 and December 31, 2024:
 June 30, 2025December 31, 2024
MillionsFair ValueUnfunded
Commitments
Fair ValueUnfunded
Commitments
Private equity funds    
Aerospace/Defense/Government$137.2 $46.3 $152.4 $49.3 
Financial services106.2 25.9 93.4 32.0 
Real estate3.6 2.2 3.7 2.4 
Total private equity funds247.0 74.4 249.5 83.7 
Hedge funds   
Long/short all cap global84.1  52.0 — 
Long/short equity financials and business services32.0  59.2 — 
Total hedge funds116.1  111.2 — 
Total private equity funds and hedge funds$363.1 $74.4 $360.7 $83.7 
Schedule investments in private equity funds subject to lock-up periods
The following table presents investments in private equity funds that were subject to lock-up periods as of June 30, 2025:
Millions1 – 3 years3 – 5 years5 – 10 years>10 yearsTotal
Private equity funds — expected lock-up period remaining$52.9$14.2$153.1$26.8$247.0
Schedule of fair value investments by level The following table presents the changes in White Mountains’s fair value measurements for Level 3 investments for the six months ended June 30, 2025 and 2024:
Level 3 Investments
MillionsOther Long-term
Investments
Other Long-term
Investments
Balance as of December 31, 2024$1,262.7 Balance as of December 31, 2023$1,138.2 
Net realized and unrealized gains63.4 Net realized and unrealized gains48.6 
Purchases and contributions68.4 Purchases and contributions.4 
Sales and distributions(1.7)Sales and distributions(41.4)
Transfers in Transfers in— 
Transfers out Transfers out— 
Balance as of June 30, 2025
$1,392.8 
Balance as of June 30, 2024
$1,145.8 
Schedule of significant unobservable inputs used in estimating the fair value of investment securities
The following tables present significant unobservable inputs used in estimating the fair value of White Mountains’s other long-term investments, classified within Level 3 as of June 30, 2025 and December 31, 2024. The tables below exclude $11.7 million and $23.4 million of Level 3 other long-term investments generally valued based on recent or expected transaction prices. The fair value of investments in private equity funds and hedge funds, bank loan funds, Lloyd’s trust deposits and ILS funds are generally estimated using the NAV of the funds.
$ in Millions
June 30, 2025
Description
Valuation Technique(s) (1)
Fair Value (2)
Unobservable Inputs
Discount Rate (5)
Terminal Cash Flow Exit Multiple (x) or Terminal Revenue Growth Rate (%) (5)
Kudu’s Participation Contracts (3)(4)
Discounted cash flow
$1,121.1
17% - 25%
7x - 22x
PassportCard/DavidShieldDiscounted cash flow$155.024%4%
ElementumDiscounted cash flow$35.022%4%
Preferred securitiesDiscounted cash flow$32.98%N/A
Private equity securities
Discounted cash flow
$21.935%4%
Private debt instrumentsDiscounted cash flow$15.2
11% - 12%
N/A
(1) Key inputs to the discounted cash flow analysis generally include projections of future revenue and earnings, discount rates and terminal exit multiples or growth rates.
(2) Includes the net unrealized investment gains (losses) associated with foreign currency; foreign currency effects based on observable inputs.
(3) Since Kudu’s Participation Contracts are not subject to corporate taxes within Kudu Investment Management, LLC, pre-tax discount rates are applied to pre-tax cash flows in determining fair values. The weighted average discount rate and weighted average terminal cash flow exit multiple applied to Kudu’s Participation Contracts was 19% and 14x.
(4) In the first six months of 2025, Kudu deployed a total of $68.2 into new and existing Participation Contracts.
(5) Increases (decreases) to the discount rates in isolation would result in lower (higher) fair value measurements, while increases (decreases) to the terminal cash flow exit multiples or terminal revenue growth rates in isolation would result in higher (lower) fair value measurements.

$ in MillionsDecember 31, 2024
Description
Valuation Technique(s) (1)
Fair Value (2)
Unobservable Inputs
Discount Rate (5)
Terminal Cash Flow Exit Multiple (x) or Terminal Revenue Growth Rate (%) (5)
Kudu’s Participation Contracts (3)(4)
Discounted cash flow
$1,008.4
17% - 25%
7x - 22x
PassportCard/DavidShield Discounted cash flow$150.024%4%
ElementumDiscounted cash flow$35.022%4%
Preferred securitiesDiscounted cash flow$31.49%N/A
Private debt instrumentsDiscounted cash flow$14.5
11% - 12%
N/A
(1) Key inputs to the discounted cash flow analysis generally include projections of future revenue and earnings, discount rates and terminal exit multiples or growth rates.
(2) Includes the net unrealized investment gains (losses) associated with foreign currency; foreign currency effects based on observable inputs.
(3) Since Kudu’s Participation Contracts are not subject to corporate taxes within Kudu Investment Management, LLC, pre-tax discount rates are applied to pre-tax cash flows in determining fair values. The weighted average discount rate and weighted average terminal cash flow exit multiple applied to Kudu’s Participation Contracts was 19% and 14x.
(4) In 2024, Kudu contributed total cash of $103.5 into new and existing Participation Contracts.
(5) Increases (decreases) to the discount rates in isolation would result in lower (higher) fair value measurements, while increases (decreases) to the terminal cash flow exit multiples or terminal revenue growth rates in isolation would result in higher (lower) fair value measurements.