v3.26.1
Fair Value Measurements (Tables)
 3 Months Ended
Mar. 31, 2026
Fair Value Disclosures [Abstract]  
Schedule of Company's Assets and Liabilities that are Measured at Fair Value on a Recurring Basis
The following tables present the Company’s assets and liabilities that are measured at fair value on a recurring basis as of March 31, 2026 and December 31, 2025, for each fair value hierarchy level: 
 Fair Value Measurements Using:
 Quoted Prices in   
 Active Markets forSignificant OtherSignificant 
 Identical AssetsObservable InputsUnobservable Inputs 
 (Level 1)(Level 2)(Level 3)Total
 (In thousands)
March 31, 2026    
Assets:    
Debt securities held in decommissioning trust fund$— $35,462 $— $35,462 
Liabilities:
Commodity derivatives — (171,158)— (171,158)
Total $— $(135,696)$— $(135,696)
December 31, 2025
Assets:
Commodity derivatives $— $50,497 $— $50,497 
Debt securities held in decommissioning trust fund— 23,707 — 23,707 
Total $— $74,204 $— $74,204 
Schedule of Costs and Fair Values of Investments in Debt Securities in Decommissioning Trust Fund
The following table summarizes the cost and fair value, purchases, proceeds from the sale and maturities, and the unrealized gains (losses) for Kosmos’ portion of the investments in debt securities held by the decommissioning trust during the three months ended March 31, 2026 and 2025:
Three Months Ended March 31,
Type of Security
Purchases
Net Proceeds (1)
Unrealized Gain (Loss)
(In thousands)
2026
Debt securities$11,843 $— $(88)
Cash and cash equivalents— 7 — 
Other(1)— 25 — 
Total$11,843 $32 $(88)
2025
Debt securities$12,206 $— $109 
Cash and cash equivalents— (747)— 
Other(1)— 143 — 
Total$12,206 $(604)$109 
(1)    Represents net receivables relating to interest.

The following table presents the costs and fair values of investments in debt securities held in the decommissioning trust fund according to the contractual maturities at March 31, 2026 and December 31, 2025:
March 31, 2026December 31, 2025
Cost
Estimated Fair Value
Cost
Estimated Fair Value
(In thousands)
Less than 5 years
$35,408 $35,462 $23,565 $23,707 
5 years to 10 years
— — — — 
Due after 10 years
— — — — 
Total
$35,408 $35,462 $23,565 $23,707 
Schedule of Carrying Values and Fair Values of Financial Instruments that are not Carried at Fair Value
The following table presents the carrying values and fair values at March 31, 2026 and December 31, 2025:
 
 March 31, 2026December 31, 2025
 Carrying ValueFair ValueCarrying ValueFair Value
 (In thousands)
7.125% Senior Notes
$— $— $99,942 $99,303 
7.750% Senior Notes
99,881 100,020 348,757 321,394 
7.500% Senior Notes
398,624 384,163 398,426 270,125 
8.750% Senior Notes
495,713 439,170 495,564 283,575 
3.125% Convertible Senior Notes
393,479 309,600 393,097 172,704 
11.250% Senior Secured Bonds
350,000 372,026 — — 
GoA Term Loan Facility196,429 196,429 150,000 150,000 
Facility1,000,000 1,000,000 1,200,000 1,200,000 
Total$2,934,126 $2,801,408 $3,085,786 $2,497,101