v3.26.1
Investments (Tables)
 6 Months Ended
Jun. 30, 2026
Investments, Debt and Equity Securities [Abstract]  
Schedule of Components of Net Investment Income
The components of net investment income for the following periods were as follows:
($ in millions)Three Months Ended
June 30,		Six Months Ended
June 30,
2026202520262025
Fixed maturity securities$75.2 $59.4 $146.4 $131.0 
Equity securities0.8 1.0 1.3 2.0 
Limited partnership interests17.2 23.2 30.4 39.5 
Short-term and other investments5.3 5.2 10.6 10.6 
Investment expenses(2.3)(3.1)(5.4)(5.9)
Net investment income - investment portfolio
96.2 85.7 183.3 177.2 
Investment income - deposit asset on reinsurance24.3 25.1 47.9 49.5 
Total net investment income(1)
$120.5 $110.8 $231.2 $226.7 
(1) In the second quarter of 2025, the Company recorded a reduction in net investment income due to an immaterial out-of-period correction of an error. See additional disclosure contained in Note 1 of the June 30, 2026 Form 10-Q.
Schedule of Net Investment Gains (Losses)
Net investment gains (losses) for the following periods were as follows:
($ in millions)Three Months Ended
June 30,		Six Months Ended
June 30,
2026202520262025
Fixed maturity securities$(0.1)$(4.1)$0.4 $(3.9)
Equity securities(0.3)(0.7)(1.6)(2.0)
Short-term investments and other0.3 (1.1)(1.1)(3.3)
Net investment gains (losses)
$(0.1)$(5.9)$(2.3)$(9.2)
The breakdown of net investment gains (losses) by transaction type for the following periods were as follows:
($ in millions)Three Months Ended
June 30,		Six Months Ended
June 30,
2026202520262025
Credit loss impairments$— $(0.9)$— $(0.9)
Intent-to-sell impairments(0.1)(2.2)(0.1)(2.2)
Total impairments(0.1)(3.1)(0.1)(3.1)
Sales and other, net4.2 2.0 6.2 4.1 
Change in fair value - equity securities(0.3)(0.7)(1.6)(1.9)
Change in fair value and gains (losses) realized
on settlements - derivatives
(3.9)(4.1)(6.8)(8.3)
Net investment gains (losses)
$(0.1)$(5.9)$(2.3)$(9.2)
Schedule of Allowance for Credit Loss Impairments on Fixed Maturity Securities
The following table presents changes in the allowance for credit loss impairments on fixed maturity securities classified as available for sale for the category of other asset-backed securities (no other categories of fixed maturity securities have an allowance for credit loss impairments):
($ in millions)Three Months Ended
June 30,		Six Months Ended
June 30,
2026202520262025
Beginning balance$2.1 $0.9 $2.1 $0.9 
Credit losses on fixed maturity securities for which credit losses were not previously reported— 3.1 — 3.1 
Net increase (decrease) related to credit losses previously reported
— (0.9)— (0.9)
Reduction of credit allowances related to sales— — — — 
Write-offs— — — — 
Ending balance$2.1 $3.1 $2.1 $3.1 
Schedule of Available-for-sale Securities Reconciliation Amortized cost, net, gross unrealized investment gains (losses) and fair values of all fixed maturity securities in the portfolio were as follows:
($ in millions)Amortized
Cost, net		Gross Unrealized
Gains		Gross Unrealized
Losses		Fair
Value
June 30, 2026
Fixed maturity securities
U.S. Government and federally
sponsored agency obligations:
Mortgage-backed securities
$699.0 $5.4 $42.2 $662.2 
Other, including U.S. Treasury securities
371.8 — 58.6 313.2 
Municipal bonds1,222.4 23.9 82.8 1,163.5 
Foreign government bonds8.6 — 0.7 7.9 
Corporate bonds2,139.1 15.2 199.8 1,954.5 
Other asset-backed securities1,684.6 7.5 26.4 1,665.7 
Totals$6,125.5 $52.0 $410.5 $5,767.0 
December 31, 2025
Fixed maturity securities
U.S. Government and federally
sponsored agency obligations:
Mortgage-backed securities$718.1 $9.5 $38.6 $689.0 
Other, including U.S. Treasury securities381.4 0.4 56.1 325.7 
Municipal bonds1,235.3 24.6 82.7 1,177.2 
Foreign government bonds10.6 — 0.6 10.0 
Corporate bonds2,064.8 27.6 182.1 1,910.3 
Other asset-backed securities1,616.5 12.0 26.1 1,602.4 
Totals$6,026.7 $74.1 $386.2 $5,714.6 
Schedule of Fair Value and Gross Unrealized Losses of Fixed Maturity Securities and Equity Securities in an Unrealized Loss Position
The following table presents the fair value and gross unrealized losses for fixed maturity securities in an unrealized loss position as of June 30, 2026 and December 31, 2025, respectively. The Company views the decrease in fair value of all of the fixed maturity securities with unrealized losses as of June 30, 2026 as due to factors other than a credit loss. As of June 30, 2026, the Company has not made the decision to sell and it is not more likely than not the Company will be required to sell the fixed maturity securities with unrealized losses before a recovery of the amortized cost basis. In reaching our conclusion that an allowance for credit is unnecessary, we considered the factors described in the evaluation of credit loss impairments for fixed maturity securities critical accounting estimate in our Annual Report on Form 10-K. In the current three months ended June 30, 2026, the performance of fixed maturity securities has been impacted by the change in interest rates, specifically interest rates being at relatively high levels compared to interest rates at the time of acquisition of the securities. In consideration of the factors, we expect to receive cash flows sufficient to recover the entire amortized cost basis of the securities in the following table.
($ in millions)12 Months or LessMore than 12 MonthsTotal
Fair ValueGross
Unrealized
Losses		Fair ValueGross
Unrealized
Losses		Fair ValueGross
Unrealized
Losses
June 30, 2026
Fixed maturity securities
U.S. Government and federally
sponsored agency obligations:
Mortgage-backed securities$174.5 $2.3 $225.5 $39.9 $400.0 $42.2 
Other
38.7 0.9 273.3 57.7 312.0 58.6 
Municipal bonds108.4 2.0 584.1 80.8 692.5 82.8 
Foreign government bonds
— — 6.9 0.7 6.9 0.7 
Corporate bonds
600.1 18.9 887.3 180.9 1,487.4 199.8 
Other asset-backed securities
404.2 3.3 285.6 23.1 689.8 26.4 
Total
$1,325.9 $27.4 $2,262.7 $383.1 $3,588.6 $410.5 
Number of positions with a
   gross unrealized loss
759 1,565 2,324 
Fair value as a percentage of total fixed
   maturity securities at fair value
23.0 %39.2 %62.2 %
December 31, 2025
Fixed maturity securities
U.S. Government and federally
sponsored agency obligations:
Mortgage-backed securities$69.7 $0.3 $247.9 $38.3 $317.6 $38.6 
Other27.1 0.4 276.1 55.7 303.2 56.1 
Municipal bonds126.0 2.8 596.4 79.9 722.4 82.7 
Foreign government bonds— — 9.0 0.6 9.0 0.6 
Corporate bonds387.3 10.5 930.6 171.6 1,317.9 182.1 
Other asset-backed securities239.5 1.2 369.8 24.9 609.3 26.1 
Total
$849.6 $15.2 $2,429.8 $371.0 $3,279.4 $386.2 
Number of positions with a
   gross unrealized loss
466 1,649 2,115 
Fair value as a percentage of total fixed
   maturity securities at fair value
14.9 %42.5 %57.4 %
Schedule of Distribution of the Company's Fixed Maturity Portfolio by Estimated Expected Maturity
With regards to fixed maturity securities that had gross unrealized losses more than 12 months, the number of positions by their respective credit ratings were as follows:
Number of Positions
June 30, 2026December 31, 2025
Credit Rating
AAA131 140 
AA823 860 
A261 275 
BBB300 317 
Total investment grade
1,515 1,592 
BB19 24 
B10 8 
CCC or lower 3 2 
Total below investment grade
32 34 
Not rated 18 23 
Totals:1,565 1,649 
The following table presents the distribution of the Company’s fixed maturity securities portfolio by estimated expected maturity. Estimated expected maturities differ from contractual maturities, reflecting assumptions regarding borrowers' utilization of the right to call or prepay obligations with or without call or prepayment penalties. For structured securities, estimated expected maturities consider broker-dealer survey prepayment assumptions and are verified for consistency with the interest rate and economic environments.
($ in millions)June 30, 2026
Amortized
Cost, net		Fair
Value
Percent of Total Fair Value
Estimated expected maturity:
Due in 1 year or less$277.8 $276.1 4.8 %
Due after 1 year through 5 years1,264.2 1,240.8 21.5 %
Due after 5 years through 10 years1,602.1 1,556.5 27.0 %
Due after 10 years through 20 years1,711.8 1,574.0 27.3 %
Due after 20 years1,269.6 1,119.6 19.4 %
Total$6,125.5 $5,767.0 100.0 %
Average option-adjusted duration, in years5.9
Schedule of Proceeds Received From Sales of Fixed Maturities and Equity Securities
Proceeds received from sales of fixed maturity and equity securities, each determined using the specific identification method, and gross gains and gross losses realized as a result of those sales for each period were as follows:
($ in millions)Three Months Ended
June 30,		Six Months Ended
June 30,
2026202520262025
Fixed maturity securities
Proceeds received
$137.8 $52.1 $231.6 $129.9 
Gross gains realized
2.4 0.5 3.9 1.7 
Gross losses realized
(2.5)(1.5)(3.4)(2.5)
Equity securities
Proceeds received
$— $6.3 $— $6.3 
Gross gains realized
— — — — 
Gross losses realized
— — — — 
Schedule of Reconciliation of Net Unrealized Investment Gains (Losses) on Fixed Maturity Securities and Equity Securities
The following table reconciles net unrealized investment gains (losses) on fixed maturity securities, net of tax, included in AOCI:
($ in millions)Three Months Ended
June 30,		Six Months Ended
June 30,
2026202520262025
Net unrealized investment gains (losses)
   on fixed maturity securities, net of tax
Beginning of period$(288.8)$(314.5)$(245.5)$(357.4)
Change in net unrealized investment gains
   (losses) on fixed maturity securities		6.8 1.4 (36.1)44.4 
Reclassification of net investment losses
   on fixed maturity securities to net income		0.1 3.2 (0.3)3.1 
End of period$(281.9)$(309.9)$(281.9)$(309.9)
Schedule of Carrying Amounts of Equity Method Limited Partnership Interests The carrying amounts of limited partnership interests were as follows:
($ in millions)
June 30, 2026December 31, 2025
Commercial mortgage loan funds$573.9 $590.7 
Real estate equity funds
107.5 127.5 
Private equity funds
150.0 118.3 
Infrastructure debt funds74.4 73.9 
Venture capital funds62.4 50.0 
Infrastructure equity funds
47.5 52.4 
Other funds(1)
85.3 87.8 
Total$1,101.0 $1,100.6 
(1)Other funds consist primarily of limited partnership interests in corporate mezzanine and private credit funds.
Schedule of Offsetting Assets and Liability The following table presents instruments that were subject to a master netting arrangement for the Company.
($ in millions)Gross
Amounts
Offset in the
Consolidated
Balance
Sheets		Net Amounts
of Assets/
Liabilities
Presented
in the
Consolidated
Balance
Sheets		Gross Amounts Not Offset
in the Consolidated
Balance Sheets
Gross
Amounts		Financial
Instruments		Cash
Collateral
Received		Net
Amount
June 30, 2026
Asset derivatives:
Free-standing derivatives$24.4 $— $24.4 $— $24.2 $0.2 
December 31, 2025
Asset derivatives:
Free-standing derivatives$21.6 $— $21.6 $— $23.8 $(2.2)