Assets and Liabilities Measured at Fair Value
The Company carries certain assets and liabilities at fair value in its Consolidated Balance Sheets. The fair value hierarchy is based on the quality of inputs used to measure fair value, with Level 1 being the highest quality and Level 3 being the lowest quality. Level 1 inputs are quoted prices in active markets for identical assets or liabilities. Level 2 inputs are observable inputs other than quoted prices included within Level 1. Level 3 inputs are unobservable inputs which reflect assumptions about pricing by market participants.

The Company's available-for-sale marketable securities consist of high quality, investment grade securities from diverse issuers. We value these securities at the closing price in the principal active markets as of the last business day of the reporting period. The fair values of the Company's marketable securities by asset class are described in Note 5 "Marketable Securities" in these consolidated financial statements for the period ended December 31, 2025. We value the deferred compensation plan assets, which consist of money market and mutual funds, based on quoted prices in active markets at the measurement date. For additional information on deferred compensation plans see also Note 13 "Employee and Retirement Benefit Plans" in these consolidated financial statements for the period ended December 31, 2025.

At the balance sheet date, the fair value of commodity derivatives contracts was determined using NYMEX quoted values. The carrying value of the Company’s Cash and cash equivalents, Accounts receivable-trade and Trade accounts payable and accrued liabilities approximates fair value. See also Note 14 "Financial Instruments and Risk Management" in these consolidated financial statements for the period ended December 31, 2025, for more information.

Financial assets and liabilities measured at fair value on a recurring basis

The following table presents the Company's financial assets and liabilities measured at fair value on a recurring basis, as of December 31, 2025 and 2024:

 December 31, 2025
(Millions of dollars)Level 1Level 2Level 3Fair Value
Financial assets
Prepaid expenses and other current assets
Fuel derivative$— $— $— $— 
Other assets
Deferred compensation plan assets18.6 — — 18.6 
 December 31, 2025
(Millions of dollars)Level 1Level 2Level 3Fair Value
Financial liabilities
Deferred credits and other liabilities
Deferred compensation plan liabilities(26.7)— — (26.7)
$(8.1)$— $— $(8.1)

December 31, 2024
(Millions of dollars)Level 1Level 2Level 3Fair Value
Financial assets
Prepaid expenses and other current assets
Fuel derivative— — 0.2 0.2 
Other assets
Deferred compensation plan assets14.9 — — 14.9 
Financial liabilities
Deferred credits and other liabilities
Deferred compensation plan liabilities(26.3)— — (26.3)
$(11.4)$— $0.2 $(11.2)

Fair value of financial instruments not recognized at fair value
The fair value of a financial instrument is the amount at which the instrument could be exchanged in a current transaction between willing parties. The table below excludes Cash and cash equivalents, Accounts receivable-trade, and Trade accounts payable and accrued liabilities, all of which had fair values approximating carrying amounts. The fair value of Current and Long-Term debt was estimated based on rates offered to the Company at that time for debt of the same maturities. The Company has off-balance sheet exposures relating to certain financial guarantees and letters of credit. The fair value of these, which represents fees associated with obtaining the instruments, was nominal.

The following table presents the carrying amounts and estimated fair values of financial instruments held by the Company at December 31, 2025 and 2024.

 December 31, 2025December 31, 2024
 CarryingLevel 2CarryingLevel 2
(Millions of dollars)AmountFair ValueAmountFair Value
Financial liabilities    
Current and long-term debt, excluding finance leases$(2,064.1)$(2,081.2)$(1,728.7)$(1,717.5)

Historical Timeline

Fiscal YearFiled
2025Feb 18, 2026Showing above
2024Feb 20, 2025
2023Feb 16, 2024
2022Feb 15, 2023
2021Feb 17, 2022
2020Feb 19, 2021
2019Feb 18, 2020
2018Feb 19, 2019
2017Feb 20, 2018
2016Feb 22, 2017
2015Feb 26, 2016

About Fair Value Disclosures

Fair value disclosures classify all assets and liabilities measured at fair value into a three-level hierarchy: Level 1 (quoted market prices), Level 2 (observable inputs like yield curves), and Level 3 (unobservable inputs requiring management estimates). The proportion of Level 3 assets directly reflects how much of the balance sheet depends on internal models rather than market evidence.

Key signals: a growing Level 3 balance relative to total fair-value assets increases valuation uncertainty and earnings volatility risk. Watch for transfers between levels — assets moving from Level 2 to Level 3 often signal deteriorating market liquidity. Unrealized gains and losses on Level 3 positions flow through earnings or other comprehensive income, so large swings deserve scrutiny. For financial institutions, examine the sensitivity disclosures that show how Level 3 valuations change under alternative assumptions. Compare the fair value of debt against its carrying amount to gauge hidden leverage.