v3.26.1
Investments (Tables)
 3 Months Ended
Mar. 31, 2026
Investments, Debt and Equity Securities [Abstract]  
Summary of Amortized Cost and Estimated Fair Value of Available-for-Sale Investments, Excluding VIE Investments Held by Successor Ambac, by Contractual Maturity
The amortized cost and estimated fair value of available-for-sale investments, by contractual maturity, were as follows:
March 31, 2026
Amortized
Cost		Estimated
Fair Value
Due in one year or less$117,446 $117,313 
Due after one year through five years47,546 45,845 
Due after five years through ten years55,344 55,042 
Due after ten years550 553 
220,886 218,753 
Residential mortgage-backed securities2,643 2,627 
Commercial mortgage-backed securities5,002 4,985 
Collateralized debt obligations1,626 1,630 
Other asset-backed securities1,380 1,392 
Total available-for-sale investments$231,537 $229,387 
December 31, 2025
Amortized
Cost		Estimated
Fair Value
Due in one year or less$180,013 $179,824 
Due after one year through five years32,409 31,588 
Due after five years through ten years47,801 47,619 
Due after ten years979 998 
261,202 260,029 
Residential mortgage-backed securities1,604 1,597 
Commercial mortgage-backed securities3,307 3,341 
Collateralized debt obligations1,963 1,975 
Other asset-backed securities1,772 1,795 
Total$269,848 $268,737 
Summary of Gross Unrealized Losses and Fair Values of Ambac's Available-for-Sale Investments
The following table shows gross unrealized losses and fair values of Octave's available-for-sale investments, which at March 31, 2026 and December 31, 2025, did not have an allowance for credit losses under the CECL standard. This information is aggregated by investment category and length of time that the individual securities have been in a continuous unrealized loss position, at March 31, 2026 and December 31, 2025:
March 31, 2026December 31, 2025
Less Than 12 Months12 Months or MoreTotalLess Than 12 Months12 Months or MoreTotal
Fair ValueGross
Unrealized
Loss		Fair ValueGross Unrealized LossFair ValueGross Unrealized LossFair 
Value		Gross
Unrealized
Loss		Fair 
Value		Gross
Unrealized
Loss		Fair 
Value		Gross
Unrealized
Loss
Fixed maturity securities:
Municipal obligations$532 $20 $4,904 $197 $5,436 $217 $535 $16 $5,820 $212 $6,355 $228 
Corporate obligations22,033 249 26,654 2,000 48,687 2,249 1,807 10 30,751 1,932 32,558 1,942 
U.S. government obligations14,522 124 6,770 94 21,292 218 2,206 14 9,491 117 11,697 131 
Residential mortgage-backed securities473 8 1,454 13 1,927 21 — — 1,596 7 1,596 7 
Commercial mortgage-backed securities2,518 40 — — 2,518 40 763 8 — — 763 8 
Collateralized debt obligations68 — — 1 68 1 — — — — — — 
Other asset-backed securities— — — — — — — — — — — — 
40,146 441 39,782 2,305 79,928 2,746 5,311 48 47,658 2,268 52,969 2,316 
Short-term— — — — — — — — — — — — 
40,146 441 39,782 2,305 79,928 2,746 5,311 48 47,658 2,268 52,969 2,316 
Total temporarily impaired securities$40,146 $441 $39,782 $2,305 $79,928 $2,746 $5,311 $48 $47,658 $2,268 $52,969 $2,316 
Summary of Amounts Included in Net Realized (Losses) Gains and Other-Than-Temporary Impairments The following table details amounts included in net investment gains (losses) and impairments included in Revenues, other, on the Consolidated Statements of Income (Loss) for the three months ended March 31, 2026 and 2025:
Three Months Ended March 31,20262025
Gross realized gains on securities$5 $— 
Gross realized losses on securities(2)(3)
Credit impairments— — 
Net investment gains (losses), including impairments$3 $(3)
Equity Method Investments [Table Text Block] O
Summary of Net Investment Income
Net investment income (loss) was comprised of the following for the three months ended March 31, 2026 and 2025:
Three Months Ended March 31,20262025
Fixed maturity securities$1,211 $1,400 
Short-term investments1,244 1,457 
Loans— 35 
Investment expense(100)2 
Securities available-for-sale and short-term2,355 2,894 
Other investments— (79)
Total net investment income (loss)$2,355 $2,815 
Debt Securities, Available-for-Sale
The amortized cost and estimated fair value of available-for-sale investments, at March 31, 2026 and December 31, 2025, were as follows:
March 31, 2026:December 31, 2025:
Amortized
Cost		Allowance for Credit Losses Gross UnrealizedEstimated
Fair Value		Amortized
Cost		Allowance for Credit LossesGross UnrealizedEstimated
Fair Value
GainsLossesGainsLosses
Fixed maturity securities:
Municipal obligations$10,606 $87 $217 $10,476 $11,697 — $121 $228 $11,590 
Corporate obligations78,891 298 2,249 76,940 67,881 — 634 1,942 66,573 
U.S. government obligations39,094 166 218 39,042 35,190 — 365 131 35,424 
Residential mortgage-backed securities2,643 5 21 2,627 1,604 — — 7 1,597 
Commercial mortgage-backed securities5,002 23 40 4,985 3,307 — 42 8 3,341 
Collateralized debt obligations1,626 5 1 1,630 1,963 — 12 — 1,975 
Other asset-backed securities1,380 12 — 1,392 1,772 — 23 — 1,795 
Total fixed maturity securities139,242 — 596 2,746 137,092 123,414 — 1,197 2,316 122,295 
Short-term investments92,295 — — — 92,295 146,434 — 8 — 146,442 
Total available-for-sale investments$231,537 $— $596 $2,746 $229,387 $269,848 — $1,205 $2,316 $268,737