v3.26.1
Fair Value Measurements (Tables)
 3 Months Ended
Mar. 31, 2026
Fair Value Disclosures [Abstract]  
Summary of Carrying Amount and Fair Value of Ambac's Financial Assets and Liabilities
The following table sets forth the carrying amount and fair value of Octave's financial assets and liabilities as of March 31, 2026 and December 31, 2025, including the level within the fair value hierarchy at which fair value measurements are categorized. As required by the Fair Value Measurement Topic of the ASC, financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement.
March 31, 2026December 31, 2025
Carrying
Amount		Total Fair
Value		Fair Value Measurements Categorized as:Carrying
Amount		Total Fair
Value		Fair Value Measurements Categorized as:
Level 1Level 2Level 3Level 1Level 2Level 3
Financial assets:
Fixed maturity securities:
Municipal obligations$10,476 $10,476 $— $10,476 $— $11,590 $11,590 $— $11,590 $— 
Corporate obligations76,940 76,940 — 76,940 — 66,573 66,573 — 66,573 — 
U.S. government obligations39,042 39,042 39,042 — — 35,424 35,424 35,424 — — 
Residential mortgage-backed securities2,627 2,627 — 2,627 — 1,597 1,597 — 1,597 — 
Commercial mortgage-backed securities4,985 4,985 — 4,985 — 3,341 3,341 — 3,341 — 
Collateralized debt obligations1,630 1,630 — 1,630 — 1,975 1,975 — 1,975 — 
Other asset-backed securities1,392 1,392 — 1,392 — 1,795 1,795 — 1,795 — 
Short term investments92,295 92,295 92,295 — — 146,442 146,442 146,442 — — 
Other investments (1)
24,971 7,454 — — — 24,971 7,454 — — — 
Cash, cash equivalents and restricted cash93,537 93,537 93,537 — — 68,440 68,440 68,440 — — 
Other assets-loans— — — — — — — — — — 
Derivative assets:
FX forward contracts— — — — — — — — — — 
Total financial assets$347,895 $330,378 $224,874 $98,050 $— $362,148 $344,631 $250,306 $86,871 $— 
Financial liabilities:
Short-term debt, including accrued interest$— $— $— $— $— $— $— $— $— $— 
Long term debt, including accrued interest118,367 118,367 — — 118,367 118,901 121,343 — — 121,343 
Derivative liabilities:
FX forward contracts426 426 — 426 — 8 8 — 8 — 
Total financial liabilities$118,793 $118,793 $— $426 $118,367 $118,909 $121,351 $— $8 $121,343 
(1)Excluded from the fair value measurement categories in the table above are investment funds of $7,454 and $7,454 as of March 31, 2026 and December 31, 2025, respectively, which are measured using NAV as a practical expedient. Also excluded from the fair value amounts in the table above are equity securities with a carrying value of $17,517 and $17,517 as of March 31, 2026 and December 31, 2025, respectively, that do not have readily determinable fair values and have carrying amounts determined using the measurement alternative.
Summary of Changes in Level 3 Fair Value Category
The following tables present the changes in the Level 3 fair value category for the periods presented in 2026 and 2025. Octave classifies financial instruments in Level 3 of the fair value hierarchy when there is reliance on at least one significant unobservable input to the valuation model. In addition to these unobservable inputs, the valuation models for Level 3 financial instruments typically also rely on a number of inputs that are readily observable either directly or indirectly. Thus, the gains and losses presented below include changes in the fair value related to both observable and unobservable inputs.
Level 3 - Financial Assets and Liabilities Accounted for at Fair Value
InvestmentsDerivativesTotal
Three Months Ended March 31, 2026:
Balance, beginning of period$— $— $— 
Total gains/(losses) realized and unrealized:
Included in earnings— — — 
Included in other comprehensive income— — — 
Purchases— — — 
Settlements— — — 
Balance, end of period$— $— $— 
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date$— $— $— 
The amount of total gains/(losses) included in other comprehensive income attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date$— $— $— 
Three Months Ended March 31, 2025:
Balance, beginning of period$— $— $— 
Total gains/(losses) realized and unrealized:
Included in earnings— — — 
Included in other comprehensive income— — — 
Purchases— — — 
Settlements— — — 
Balance, end of period$— $— $— 
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date$— $— $— 
The amount of total gains/(losses) included in other comprehensive income attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date$—$—$—
Level 3 - Financial Assets and Liabilities Accounted for at Fair Value
InvestmentsDerivativesTotal
Three Months Ended March 31, 2026:
Balance, beginning of period$— $— $— 
Total gains/(losses) realized and unrealized:
Included in earnings— — — 
Included in other comprehensive income— — — 
Settlements— — — 
Balance, end of period$— $— $— 
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date$— $— $— 
The amount of total gains/(losses) included in other comprehensive income attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date$— $— $— 
Three Months Ended March 31, 2025:
Balance, beginning of period$— $— $— 
Total gains/(losses) realized and unrealized:
Included in earnings— — — 
Included in other comprehensive income— — — 
Settlements— — — 
Balance, end of period$— $— $— 
The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date$— $— $— 
The amount of total gains/(losses) included in other comprehensive income attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date$— $— $— 
Summary of Gains and Losses (Realized and Unrealized) Relating to Level 3 Assets and Liabilities Included in Earnings
Gains and losses (realized and unrealized) relating to Level 3 assets and liabilities included in earnings for the three months ended March 31, 2026 and 2025 are reported as follows:
Three Months Ended March 31, 2026Three Months Ended March 31, 2025
Net
Investment
Income		Net Gains
(Losses) on
Derivative
Contracts		Other
Income or
(Expense)		Net
Investment
Income		Net Gains
(Losses) on
Derivative
Contracts		Other
Income or
(Expense)
Total gains (losses) included in earnings for the period$—$—$—$—$—$—
Changes in unrealized gains (losses) relating to financial instruments still held at the reporting date——————