v3.26.1
Investments (Tables)
12 Months Ended
Dec. 31, 2025
Investments, Debt and Equity Securities [Abstract]  
Summary of Investment Income The following table summarizes net investment income for the twelve months ended December 31, 2025, 2024 and 2023:
Twelve Months Ended
December 31, 2025December 31, 2024December 31, 2023
 ($ in millions)
Fixed income securities — Available for sale$214.2 $161.5 $115.7 
Fixed income securities — Trading65.9 88.2 98.9 
Short-term investments — Available for sale3.7 4.5 5.3 
Short-term investments — Trading0.3 0.1 0.3 
Fixed term deposits (included in cash and cash equivalents)39.1 45.3 39.9 
Catastrophe bonds — Trading— — 0.2 
Privately-held investments — Available for sale
1.9 1.2 0.1 
Privately-held investments — Trading16.7 34.9 44.7 
Equity securities
0.3 — — 
Other investments, at fair value (1)
(5.8)(6.2)(17.8)
Total336.3 329.5 287.3 
Investment expenses(10.0)(11.5)(11.6)
Net investment income$326.3 $318.0 $275.7 
_____________
(1)    Other investments primarily represent the Company’s investments in investment funds. The amount reported represents the change in fair value of the investment funds in the period.
Net Realized and Unrealized Investment Gains and Losses and Change in Unrealized Gains and Losses on Investments
The following table summarizes the net realized and unrealized investment gains and losses recorded in the consolidated statement of operations and the change in unrealized gains and losses on investments recorded in other comprehensive income for the twelve months ended December 31, 2025, 2024 and 2023:
Twelve Months Ended
December 31, 2025December 31, 2024December 31, 2023
($ in millions)
Available for sale:
Fixed income securities — gross realized gains$23.2 $2.4 $1.6 
Fixed income securities — gross realized (losses)(67.0)(60.6)(41.5)
Short-term investments — gross realized gains2.6 0.8 0.6 
Short-term investments — gross realized (losses)(1.8)(2.0)(0.9)
Net decrease in allowance for credit losses0.7 1.9 4.8 
Trading:
Fixed income securities — gross realized gains1.8 1.2 1.0 
Fixed income securities — gross realized (losses)(1.4)(10.0)(3.5)
Fixed income securities — net unrealized gains24.8 26.8 65.9 
Short-term investments — gross realized gains— — 0.1 
Short-term investments — gross realized (losses)— (0.3)(0.3)
Privately-held investments — gross realized gains2.1 0.8 0.8 
Privately-held investments — gross realized (losses)(2.1)(28.8)— 
Privately-held investments — net unrealized gains/(losses)
1.9 18.6 (15.2)
Catastrophe bonds — net unrealized gains
— — 0.1 
Investments, equity method:
Net unrealized gains/(losses)2.3 (0.1)1.0 
Gross realized (losses)— (0.2)— 
Equity securities - unrealized gains 2.0 — — 
Total net realized and unrealized investment (losses)/gains recorded in the consolidated statement of operations
$(10.9)$(49.5)$14.5 
Change in available for sale net unrealized gains/(losses):
Available for sale investments
$171.0 $34.1 $126.2 
Income tax (expense)(34.1)(4.7)(20.6)
Total change in net unrealized gains/(losses), net of taxes recorded in other comprehensive income
$136.9 $29.4 $105.6 
Cost or Amortized Cost, Unrealized and Realized Gains and Losses and Estimated Fair Value of Available for Sale Investments The following tables present the cost or amortized cost, gross unrealized gains and losses, and estimated fair market value of available for sale investments in fixed income securities, short-term investments and privately-held investments as at December 31, 2025 and December 31, 2024:
 As at December 31, 2025
 
Cost or Amortized Cost
Gross Unrealized Gains
Gross Unrealized Losses
Allowance for Credit Losses
Fair Market Value
 ($ in millions)
Fixed income securities, available for sale
U.S. government$1,206.4 $20.1 $(4.5)$— $1,222.0 
U.S. agency2.0 — — — 2.0 
Municipal90.9 1.6 (0.2)— 92.3 
Corporate1,995.2 26.8 (24.1)(0.3)1,997.6 
Non-U.S. government-backed corporate66.0 0.8 (0.5)— 66.3 
Non-U.S. government400.6 2.1 (1.1)— 401.6 
Asset-backed499.5 2.0 (0.5)— 501.0 
Agency commercial mortgage-backed
9.8 — (0.3)— 9.5 
Agency residential mortgage-backed
740.6 7.5 (27.0)— 721.1 
Total fixed income securities, available for sale
5,011.0 60.9 (58.2)(0.3)5,013.4 
Short-term investments, available for sale
45.4 — — — 45.4 
Privately-held investments, available for sale
Asset-backed securities15.8 0.5 — — 16.3 
Global corporate securities33.8 0.4 — — 34.2 
Total privately-held investments, available for sale49.6 0.9 — — 50.5 
Total investments, available for sale
$5,106.0 $61.8 $(58.2)$(0.3)$5,109.3 
 As at December 31, 2024
 
Cost or Amortized Cost
Gross Unrealized Gains
Gross Unrealized Losses
Allowance for Credit Losses
Fair Market Value
 ($ in millions)
Fixed income securities, available for sale
U.S. government$1,504.8 $1.5 $(25.7)$— $1,480.6 
U.S. agency7.5 — (0.3)— 7.2 
Municipal84.2 — (1.9)— 82.3 
Corporate2,045.3 8.5 (66.4)(1.0)1,986.4 
Non-U.S. government-backed corporate132.9 0.8 (2.4)— 131.3 
Non-U.S. government248.2 1.0 (2.4)— 246.8 
Asset-backed232.4 2.2 (0.1)— 234.5 
Agency commercial mortgage-backed5.0 — (0.6)— 4.4 
Agency residential mortgage-backed600.8 — (82.1)— 518.7 
Total fixed income securities, available for sale
4,861.1 14.0 (181.9)(1.0)4,692.2 
Short-term investments, available for sale
261.9 — — — 261.9 
Privately-held investments, available for sale
Asset-backed securities24.0 0.2 — — 24.2 
Total investments, available for sale
$5,147.0 $14.2 $(181.9)$(1.0)$4,978.3 
Cost, Gross Unrealized Gains and Losses, and Estimated Fair Value of Trading Investments in Fixed Income Maturities The following tables present the cost or amortized cost, gross unrealized gains and losses, and estimated fair market value of trading investments in fixed income securities, short-term investments, catastrophe bonds and privately-held investments as at December 31, 2025 and December 31, 2024:
 As at December 31, 2025
 
Cost or Amortized Cost
Gross Unrealized Gains
Gross Unrealized Losses
Fair Market Value
 ($ in millions)
Fixed income securities, trading
U.S. government$259.2 $5.1 $(0.4)$263.9 
Municipal4.7 — — 4.7 
Corporate141.4 1.8 (2.0)141.2 
High yield loans99.6 0.6 (0.2)100.0 
Non-U.S. government37.6 0.2 (0.2)37.6 
Asset-backed461.8 1.4 (2.5)460.7 
Agency mortgage-backed33.5 0.3 (1.7)32.1 
Total fixed income securities, trading
1,037.8 9.4 (7.0)1,040.2 
Privately-held investments, trading
Commercial mortgage loans25.3 0.1 — 25.4 
Middle market loans and other private debt32.0 0.1 (3.2)28.9 
Asset-backed securities63.8 3.9 (0.2)67.5 
Total privately-held investments, trading
121.1 4.1 (3.4)121.8 
Total investments, trading
$1,158.9 $13.5 $(10.4)$1,162.0 
 As at December 31, 2024
 
Cost or Amortized Cost
Gross Unrealized Gains
Gross Unrealized Losses
Fair Market Value
 ($ in millions)
Fixed income securities, trading
U.S. government$262.9 $0.6 $(2.2)$261.3 
Municipal1.6 — — 1.6 
Corporate155.5 0.5 (4.9)151.1 
High yield loans101.7 0.9 (0.2)102.4 
Non-U.S. government-backed corporate2.8 — — 2.8 
Non-U.S. government24.4 0.1 (0.1)24.4 
Asset-backed624.6 4.1 (3.5)625.2 
Agency mortgage-backed 34.2 — (3.1)31.1 
Total fixed income securities, trading
1,207.7 6.2 (14.0)1,199.9 
Short-term investments, trading
1.0 — — 1.0 
Catastrophe bonds, trading
1.0 — — 1.0 
Privately-held investments, trading
Commercial mortgage loans80.9 0.5 (1.7)79.7 
Middle market loans and other private debt61.6 0.1 (0.7)61.0 
Asset-backed securities126.7 0.9 — 127.6 
Global corporate securities18.8 — (0.3)18.5 
Total privately-held investments, trading
288.0 1.5 (2.7)286.8 
Total investments, trading
$1,497.7 $7.7 $(16.7)$1,488.7 
Equity Method Investments
The table below shows the Company’s equity method investments for the twelve months ended December 31, 2025 and 2024:
Carrying Value
 ($ in millions)
Opening undistributed value of investment as at January 1, 2025
$7.3 
Unrealized gain for the twelve months to December 31, 2025
2.3 
Closing value of investment as at December 31, 2025
$9.6 
Opening undistributed value of investment as at January 1, 2024
$7.6 
Unrealized (loss)/gain for the twelve months to December 31, 2024
(0.1)
Realized (loss) for the twelve months to December 31, 2024
(0.2)
Closing value of investments at December 31, 2024
$7.3 
Summary of Fixed Maturities The scheduled maturity distribution of the Company’s available for sale securities as at December 31, 2025 and December 31, 2024 is set forth below. Actual maturities may differ from contractual maturities because issuers of securities may have the right to call or prepay obligations with or without call or prepayment penalties.
 As at December 31, 2025
 
Amortized Cost or Cost
Fair Market Value
 ($ in millions)
Due one year or less$257.6 $257.5 
Due after one year through five years2,095.2 2,103.8 
Due after five years through ten years1,390.4 1,402.9 
Due after ten years97.1 97.2 
3,840.3 3,861.4 
Agency commercial mortgage-backed
9.8 9.5 
Agency residential mortgage-backed
740.6 721.1 
Asset-backed securities515.3 517.3 
Total investments, available for sale
$5,106.0 $5,109.3 
 At December 31, 2024
 
Amortized Cost or Cost
Fair Market Value
 ($ in millions)
Due one year or less$834.1 $831.2 
Due after one year through five years2,386.5 2,353.2 
Due after five years through ten years1,060.7 1,008.7 
Due after ten years3.5 3.4 
4,284.8 4,196.5 
Agency commercial mortgage-backed5.0 4.4 
Agency residential mortgage-backed600.8 518.7 
Asset-backed securities256.4 258.7 
Total investments, available for sale
$5,147.0 $4,978.3 
Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value The following tables summarize, by type of security, the aggregate fair value and gross unrealized loss by length of time the security has been in an unrealized loss position for the Company’s available for sale portfolio as at December 31, 2025 and December 31, 2024:
 December 31, 2025
 0-12 monthsOver 12 monthsTotal
 
Fair Market Value
Gross Unrealized Losses
Fair Market Value
Gross Unrealized Losses
Fair Market Value
Gross Unrealized Losses
Number of Securities
 
($ in millions, except number of securities)
Fixed income securities, available for sale
U.S. government$152.2 $(1.2)$123.1 $(3.3)$275.3 $(4.5)43
Municipal5.5 — 14.1 (0.2)19.6 (0.2)14
Corporate253.1 (1.2)387.7 (22.9)640.8 (24.1)302
Non-U.S. government-backed corporate7.7 (0.1)23.7 (0.4)31.4 (0.5)5
Non-U.S. government89.2 (0.6)17.4 (0.5)106.6 (1.1)40
Asset-backed167.5 (0.5)— — 167.5 (0.5)60
Agency commercial mortgage-backed — — 4.7 (0.3)4.7 (0.3)1
Agency residential mortgage-backed71.4 (0.1)177.5 (26.9)248.9 (27.0)141
Total fixed income securities, available for sale$746.6 $(3.7)$748.2 $(54.5)$1,494.8 $(58.2)606
 December 31, 2024
 0-12 monthsOver 12 monthsTotal
 
Fair Market Value
Gross Unrealized Losses
Fair Market Value
Gross Unrealized Losses
Fair Market Value
Gross Unrealized Losses
Number of Securities
 
($ in millions, except number of securities)
Fixed income securities, available for sale
U.S. government$718.1 $(11.6)$397.8 $(14.1)$1,115.9 $(25.7)137
U.S. agency— — 7.2 (0.3)7.2 (0.3)1
Municipal33.6 (0.7)45.4 (1.2)79.0 (1.9)47
Corporate570.3 (6.8)663.9 (59.6)1,234.2 (66.4)692
Non-U.S. government-backed corporate5.8 — 91.1 (2.4)96.9 (2.4)12
Non-U.S. government118.8 (0.9)43.7 (1.5)162.5 (2.4)41
Asset-backed17.2 (0.1)— — 17.2 (0.1)14
Agency commercial mortgage-backed— — 4.5 (0.6)4.5 (0.6)1
Agency residential mortgage-backed161.2 (2.2)351.3 (79.9)512.5 (82.1)225
Total fixed income securities, available for sale$1,625.0 $(22.3)$1,604.9 $(159.6)$3,229.9 $(181.9)1,170