v3.26.1
Investments (Tables)
 6 Months Ended
Jun. 30, 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 and short-term investments, by contractual maturity, as of June 30, 2026 and December 31, 2025, were as follows:
June 30, 2026
Amortized
Cost		Estimated
Fair Value
Due in one year or less$97,346 $97,257 
Due after one year through five years57,023 54,884 
Due after five years through ten years54,868 54,483 
Due after ten years— — 
209,237 206,624 
Residential mortgage-backed securities2,452 2,428 
Commercial mortgage-backed securities4,869 4,848 
Collateralized debt obligations1,368 1,368 
Other asset-backed securities1,380 1,386 
Total$219,306 $216,654 
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 and short-term investments, which at June 30, 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 June 30, 2026 and December 31, 2025:
June 30, 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$1,194 $14 $4,575 $187 $5,769 $201 $535 $16 $5,820 $212 $6,355 $228 
Corporate obligations25,390 299 24,024 1,956 49,414 2,255 1,807 10 30,751 1,932 32,558 1,942 
U.S. government obligations30,226 353 4,724 76 34,950 429 2,206 14 9,491 117 11,697 131 
Residential mortgage-backed securities1,070 11 1,357 13 2,427 24 — — 1,596 7 1,596 7 
Commercial mortgage-backed securities2,515 41 — — 2,515 41 763 8 — — 763 8 
Collateralized debt obligations593 1 — — 593 1 — — — — — — 
Other asset-backed securities— — — — — — — — — — — — 
Total fixed maturity securities60,988 719 34,680 2,232 95,668 2,951 5,311 48 47,658 2,268 52,969 2,316 
Short-term investments— — — — — — — — — — — — 
Total temporarily impaired securities$60,988 $719 $34,680 $2,232 $95,668 $2,951 $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 periods presented:
Three Months Ended June 30,Six Months Ended June 30,
2026202520262025
Gross realized gains on securities$63 $2 $68 $2 
Gross realized losses on securities— — (2)(3)
Credit impairments— — — — 
Net investment gains (losses), including impairments$63 $2 $66 $(1)
Summary of Net Investment Income
Net investment income (loss) was comprised of the following for the periods presented:
Three Months Ended June 30,Six Months Ended June 30,
2026202520262025
Fixed maturity securities$1,280 $1,470 $2,491 $2,870 
Short-term investments907 1,191 2,151 2,648 
Loans— 35 — 69 
Other investments(103)— (103)— 
Fixed maturity securities - trading— — — (79)
Investment expense(207)(87)(307)(84)
Total net investment income (loss)$1,877 $2,609 $4,232 $5,424 
Debt Securities, Available-for-Sale
The amortized cost and estimated fair value of available-for-sale investments and short-term investments, as of June 30, 2026 and December 31, 2025, were as follows:
June 30, 2026December 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$10,256 $— $36 $201 $10,091 $11,697 — $121 $228 $11,590 
Corporate obligations75,283 — 176 2,255 73,204 67,881 — 634 1,942 66,573 
U.S. government obligations41,185 — 60 429 40,816 35,190 — 365 131 35,424 
Residential mortgage-backed securities2,452 — — 24 2,428 1,604 — — 7 1,597 
Commercial mortgage-backed securities4,869 — 20 41 4,848 3,307 — 42 8 3,341 
Collateralized debt obligations1,368 — 1 1 1,368 1,963 — 12 — 1,975 
Other asset-backed securities1,380 — 6 — 1,386 1,772 — 23 — 1,795 
Total fixed maturity securities136,793 — 299 2,951 134,141 123,414 — 1,197 2,316 122,295 
Short-term investments82,513 — — — 82,513 146,434 — 8 — 146,442 
Total$219,306 $— $299 $2,951 $216,654 $269,848 — $1,205 $2,316 $268,737