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Investments (Tables) | 3 Months Ended
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Mar. 31, 2024
Investments [Abstract] |
Schedule of Available-for-Sale Securities | Information regarding our AFS securities as of March 31, 2024 and December 31, 2023, were as follows:
March 31, 2024 |  | Cost/ Amortized Cost |  | Allowance for Credit Losses |  | Unrealized Gains |  | Unrealized Losses |  | Fair Value
($ in thousands) |  |  |  |  |
AFS fixed income securities: |  |  |  |  |  |  |  |  |  |
U.S. government and government agencies |  | $ | 161,335 |  |  | — |  |  | 70 |  |  | (19,579) |  |  | 141,826 |
Foreign government |  | 10,703 |  |  | (29) |  |  | — |  |  | (1,445) |  |  | 9,229 |
Obligations of states and political subdivisions |  | 570,438 |  |  | (695) |  |  | 1,101 |  |  | (31,858) |  |  | 538,986 |
Corporate securities |  | 2,930,310 |  |  | (15,442) |  |  | 20,367 |  |  | (140,185) |  |  | 2,795,050 |
Collateralized loan obligations ("CLO") and other asset-backed securities ("ABS") |  | 1,958,551 |  |  | (2,627) |  |  | 15,158 |  |  | (73,997) |  |  | 1,897,085 |
Residential mortgage-backed securities ("RMBS") |  | 1,623,948 |  |  | (11,580) |  |  | 3,828 |  |  | (104,237) |  |  | 1,511,959 |
Commercial mortgage-backed securities ("CMBS") |  | 727,986 |  |  | (8) |  |  | 1,103 |  |  | (39,712) |  |  | 689,369 |
Total AFS fixed income securities |  | $ | 7,983,271 |  |  | (30,381) |  |  | 41,627 |  |  | (411,013) |  |  | 7,583,504 |
December 31, 2023 |  | Cost/ Amortized Cost |  | Allowance for Credit Losses |  | Unrealized Gains |  | Unrealized Losses |  | Fair Value
($ in thousands) |  |  |  |  |
AFS fixed income securities: |  |  |  |  |  |  |  |  |  |
U.S. government and government agencies |  | $ | 223,157 |  |  | — |  |  | 139 |  |  | (18,261) |  |  | 205,035 |
Foreign government |  | 11,140 |  |  | (35) |  |  | — |  |  | (1,302) |  |  | 9,803 |
Obligations of states and political subdivisions |  | 612,938 |  |  | (669) |  |  | 2,623 |  |  | (28,927) |  |  | 585,965 |
Corporate securities |  | 2,834,048 |  |  | (12,999) |  |  | 28,078 |  |  | (137,888) |  |  | 2,711,239 |
CLO and other ABS |  | 1,911,831 |  |  | (2,854) |  |  | 11,855 |  |  | (86,005) |  |  | 1,834,827 |
RMBS |  | 1,568,960 |  |  | (11,649) |  |  | 6,023 |  |  | (85,851) |  |  | 1,477,483 |
CMBS |  | 718,623 |  |  | (6) |  |  | 1,358 |  |  | (45,130) |  |  | 674,845 |
Total AFS fixed income securities |  | $ | 7,880,697 |  |  | (28,212) |  |  | 50,076 |  |  | (403,364) |  |  | 7,499,197 |
Schedule of Debt Securities, Available-for-Sale, Allowance for Credit Loss | The following tables provide a roll forward of the allowance for credit losses on our AFS fixed income securities for the indicated periods:
Quarter ended March 31, 2024 |  | Beginning Balance |  | Current Provision for Securities without Prior Allowance |  | Initial Allowance for Purchased Credit Deteriorated Assets with Credit Deterioration |  | Increase (Decrease) on Securities with Prior Allowance, excluding intent (or Requirement) to Sell Securities |  | Reductions for Securities Sold |  | Reductions for Securities Identified as Intent (or Requirement) to Sell during the Period |  | Ending Balance
($ in thousands) |  |  |  |  |  |  |
Foreign government |  | $ | 35 |  |  | — |  |  | — |  |  | — |  |  | (6) |  |  | — |  |  | 29 |
Obligations of states and political subdivisions |  | 669 |  |  | 9 |  |  | — |  |  | 25 |  |  | (8) |  |  | — |  |  | 695 |
Corporate securities |  | 12,999 |  |  | 1,015 |  |  | — |  |  | 1,792 |  |  | (355) |  |  | (9) |  |  | 15,442 |
CLO and other ABS |  | 2,854 |  |  | 90 |  |  | — |  |  | (314) |  |  | (3) |  |  | — |  |  | 2,627 |
RMBS |  | 11,649 |  |  | — |  |  | — |  |  | 31 |  |  | (100) |  |  | — |  |  | 11,580 |
CMBS |  | 6 |  |  | 2 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 8 |
Total AFS fixed income securities |  | $ | 28,212 |  |  | 1,116 |  |  | — |  |  | 1,534 |  |  | (472) |  |  | (9) |  |  | 30,381 |
Quarter ended March 31, 2023 |  | Beginning Balance |  | Current Provision for Securities without Prior Allowance |  | Initial Allowance for Purchased Credit Deteriorated Assets with Credit Deterioration |  | Increase (Decrease) on Securities with Prior Allowance, excluding intent (or Requirement) to Sell Securities |  | Reductions for Securities Sold |  | Reductions for Securities Identified as Intent (or Requirement) to Sell during the Period |  | Ending Balance
($ in thousands) |  |  |  |  |  |  |
Foreign government |  | $ | 284 |  |  | — |  |  | — |  |  | (248) |  |  | — |  |  | — |  |  | 36 |
Obligations of states and political subdivisions |  | 1,024 |  |  | 50 |  |  | — |  |  | (254) |  |  | (83) |  |  | — |  |  | 737 |
Corporate securities |  | 30,330 |  |  | 2,854 |  |  | — |  |  | (13,964) |  |  | (2,453) |  |  | (11) |  |  | 16,756 |
CLO and other ABS |  | 2,375 |  |  | 787 |  |  | — |  |  | 736 |  |  | (3) |  |  | — |  |  | 3,895 |
RMBS |  | 11,597 |  |  | 12 |  |  | — |  |  | 219 |  |  | (88) |  |  | — |  |  | 11,740 |
CMBS |  | 111 |  |  | 27 |  |  | — |  |  | 252 |  |  | — |  |  | — |  |  | 390 |
Total AFS fixed income securities |  | $ | 45,721 |  |  | 3,730 |  |  | — |  |  | (13,259) |  |  | (2,627) |  |  | (11) |  |  | 33,554 |
Schedule of Quantitative Information about Unrealized Losses on AFS | Quantitative information about unrealized losses on our AFS portfolio follows:
March 31, 2024 |  | Less than 12 months |  | 12 months or longer |  | Total
($ in thousands) |  | Fair Value |  | Unrealized Losses |  | Fair Value |  | Unrealized Losses |  | Fair Value |  | Unrealized Losses
AFS fixed income securities: |  |  |  |  |  |  |  |  |  |  |  |
U.S. government and government agencies |  | $ | 8,149 |  |  | (49) |  |  | 107,151 |  |  | (19,530) |  |  | 115,300 |  |  | (19,579) |
Foreign government |  | — |  |  | — |  |  | 9,229 |  |  | (1,445) |  |  | 9,229 |  |  | (1,445) |
Obligations of states and political subdivisions |  | 161,084 |  |  | (1,289) |  |  | 303,259 |  |  | (30,569) |  |  | 464,343 |  |  | (31,858) |
Corporate securities |  | 316,330 |  |  | (4,043) |  |  | 1,446,157 |  |  | (136,142) |  |  | 1,762,487 |  |  | (140,185) |
CLO and other ABS |  | 385,471 |  |  | (7,527) |  |  | 824,843 |  |  | (66,470) |  |  | 1,210,314 |  |  | (73,997) |
RMBS |  | 511,009 |  |  | (8,770) |  |  | 761,356 |  |  | (95,467) |  |  | 1,272,365 |  |  | (104,237) |
CMBS |  | 133,266 |  |  | (2,033) |  |  | 494,395 |  |  | (37,679) |  |  | 627,661 |  |  | (39,712) |
Total AFS fixed income securities |  | $ | 1,515,309 |  |  | (23,711) |  |  | 3,946,390 |  |  | (387,302) |  |  | 5,461,699 |  |  | (411,013) |
December 31, 2023 |  | Less than 12 months |  | 12 months or longer |  | Total
($ in thousands) |  | Fair Value |  | Unrealized Losses |  | Fair Value |  | Unrealized Losses |  | Fair Value |  | Unrealized Losses
AFS fixed income securities: |  |  |  |  |  |  |  |  |  |  |  |
U.S. government and government agencies |  | $ | 77,698 |  |  | (188) |  |  | 108,578 |  |  | (18,073) |  |  | 186,276 |  |  | (18,261) |
Foreign government |  | 1,552 |  |  | (87) |  |  | 8,251 |  |  | (1,215) |  |  | 9,803 |  |  | (1,302) |
Obligations of states and political subdivisions |  | 137,031 |  |  | (962) |  |  | 290,964 |  |  | (27,965) |  |  | 427,995 |  |  | (28,927) |
Corporate securities |  | 263,423 |  |  | (6,369) |  |  | 1,439,422 |  |  | (131,519) |  |  | 1,702,845 |  |  | (137,888) |
CLO and other ABS |  | 278,940 |  |  | (7,120) |  |  | 984,175 |  |  | (78,885) |  |  | 1,263,115 |  |  | (86,005) |
RMBS |  | 351,976 |  |  | (4,765) |  |  | 757,914 |  |  | (81,086) |  |  | 1,109,890 |  |  | (85,851) |
CMBS |  | 130,189 |  |  | (2,995) |  |  | 471,256 |  |  | (42,135) |  |  | 601,445 |  |  | (45,130) |
Total AFS fixed income securities |  | $ | 1,240,809 |  |  | (22,486) |  |  | 4,060,560 |  |  | (380,878) |  |  | 5,301,369 |  |  | (403,364) |
Schedule of Fixed Maturity Securities by Contractual Maturities | AFS and held-to-maturity ("HTM") fixed income securities at March 31, 2024, by contractual maturity are shown below. The maturities of RMBS, CMBS, CLO and other ABS securities were calculated using each security's estimated average life. Expected maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties.
|  | AFS |  | HTM
($ in thousands) |  | Fair Value |  | Carrying Value |  | Fair Value
Due in one year or less |  | $ | 582,163 |  |  | — |  |  | — |
Due after one year through five years |  | 3,435,983 |  |  | 15,716 |  |  | 14,898 |
Due after five years through 10 years |  | 2,833,659 |  |  | 4,579 |  |  | 4,285 |
Due after 10 years |  | 731,699 |  |  | — |  |  | — |
Total fixed income securities |  | $ | 7,583,504 |  |  | 20,295 |  |  | 19,183 |
Schedule of Alternative Investment Portfolio by Strategyand Remaining Commitment Amount and Maximum Exposure to Loss Associated with Each Strategy | The following table summarizes our alternative investment portfolio by strategy:
|  | March 31, 2024 |  | December 31, 2023
($ in thousands) |  | Carrying Value |  | Remaining Commitment |  | Maximum Exposure to Loss |  | Carrying Value |  | Remaining Commitment |  | Maximum Exposure to Loss
Alternative Investments |  |  |  |  |  |  |  |  |  |  |  |
Private equity |  | $ | 306,444 |  |  | 137,986 |  |  | 444,430 |  |  | 301,759 |  |  | 131,885 |  |  | 433,644 |
Private credit |  | 53,392 |  |  | 90,569 |  |  | 143,961 |  |  | 54,500 |  |  | 89,401 |  |  | 143,901 |
Real assets |  | 42,853 |  |  | 31,100 |  |  | 73,953 |  |  | 39,520 |  |  | 33,040 |  |  | 72,560 |
Total alternative investments |  | $ | 402,689 |  |  | 259,655 |  |  | 662,344 |  |  | 395,779 |  |  | 254,326 |  |  | 650,105 |
Schedule of Aggregated Summarized Income Statement Financial Information for Partnerships in Alternative Investment Portfolio | The following table shows gross summarized financial information for our alternative investments portfolio, including the portion we do not own. As the majority of these investments report results to us on a one quarter lag, the summarized financial statement information is for the three-month period ended December 31:
Income Statement Information |  | Quarter ended March 31, |  |
($ in millions) |  | 2024 |  | 2023 |  |  |  |
Net investment income (loss) |  | $ | (346.0) |  |  | (70.7) |  |  |  |  |
Realized gains |  | 1,830.8 |  |  | 1,722.3 |  |  |  |  |
Net change in unrealized appreciation (depreciation) |  | 3,819.0 |  |  | 1,443.7 |  |  |  |  |
Net income |  | $ | 5,303.8 |  |  | 3,095.3 |  |  |  |  |
Alternative investment income included in "Net investment income earned" on our Consolidated Statements of Income |  | $ | 6.9 |  |  | 7.8 |  |  |  |  |
Schedule of Securities Pledged as Collateral | The following table summarizes the market value of these securities at March 31, 2024:
($ in millions) |  | FHLBI Collateral |  | FHLBNY Collateral |  |  |  | State and Regulatory Deposits |  | Total
U.S. government and government agencies |  | $ | — |  |  | — |  |  |  |  | 20.0 |  |  | 20.0 |
Obligations of states and political subdivisions |  | — |  |  | — |  |  |  |  | 4.2 |  |  | 4.2 |
RMBS |  | 66.2 |  |  | 24.1 |  |  |  |  | — |  |  | 90.3 |
CMBS |  | 2.3 |  |  | 8.5 |  |  |  |  | — |  |  | 10.8 |
Total pledged as collateral |  | $ | 68.5 |  |  | 32.6 |  |  |  |  | 24.2 |  |  | 125.3 |
Schedule of Pre-Tax Net Investment Income Earned | The components of pre-tax net investment income earned were as follows:
|  | Quarter ended March 31, |  |
($ in thousands) |  | 2024 |  | 2023 |  |  |  |
Fixed income securities |  | $ | 94,102 |  |  | 80,087 |  |  |  |  |
Commercial mortgage loans ("CMLs") |  | 2,794 |  |  | 1,965 |  |  |  |  |
Equity securities |  | 4,908 |  |  | 1,205 |  |  |  |  |
Short-term investments |  | 3,519 |  |  | 4,650 |  |  |  |  |
Alternative investments |  | 6,881 |  |  | 7,768 |  |  |  |  |
Other investments |  | 263 |  |  | 43 |  |  |  |  |
Investment expenses |  | (4,618) |  |  | (4,212) |  |  |  |  |
Net investment income earned |  | $ | 107,849 |  |  | 91,506 |  |  |  |  |
Schedule of Realized and Unrealized Gains (Losses) on Securities | The following table summarizes net realized and unrealized investment gains and losses for the periods indicated:
|  | Quarter ended March 31, |  |
($ in thousands) |  | 2024 |  | 2023 |  |  |  |
Gross gains on sales |  | $ | 2,135 |  |  | 3,784 |  |  |  |  |
Gross losses on sales |  | (1,965) |  |  | (12,930) |  |  |  |  |
Net realized gains (losses) on disposals |  | 170 |  |  | (9,146) |  |  |  |  |
Net unrealized gains (losses) on equity securities |  | 692 |  |  | 3,248 |  |  |  |  |
Net credit loss benefit (expense) on fixed income securities, AFS |  | (2,650) |  |  | 9,529 |  |  |  |  |
Net credit loss benefit (expense) on CMLs |  | 168 |  |  | 17 |  |  |  |  |
Losses on securities for which we have the intent to sell |  | (15) |  |  | (304) |  |  |  |  |
Net realized and unrealized investment gains (losses) |  | $ | (1,635) |  |  | 3,344 |  |  |  |  |
Schedule of Unrealized Gain (Loss) on Equity Securities | Net unrealized gains and losses recognized in income on equity securities, as reflected in the table above, included the following:
|  | Quarter ended March 31, |  |
($ in thousands) |  | 2024 |  | 2023 |  |  |  |
Unrealized gains (losses) recognized in income on equity securities: |  |  |  |  |  |  |  |
On securities remaining in our portfolio at end of period |  | $ | 692 |  |  | (142) |  |  |  |  |
On securities sold in period |  | — |  |  | 3,390 |  |  |  |  |
Total unrealized gains (losses) recognized in income on equity securities |  | $ | 692 |  |  | 3,248 |  |  |  |  |

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