v3.26.1
Fair Value Measurements
 6 Months Ended
Jun. 30, 2026
Fair Value Disclosures [Abstract]  
Fair Value Measurements
10.    Fair Value Measurements
We measure and classify certain of our assets and liabilities at fair value in accordance with the hierarchy as defined by the Fair Value Measurement Topic of the FASB ASC. The fair value hierarchy provides transparency regarding the inputs we use to measure fair value. We categorize each fair value measurement in its entirety into the following three levels, based on the lowest level input that is significant to the entire measurement:
•Level 1 Inputs - quoted prices (unadjusted) in active markets for identical assets or liabilities that we can access at the measurement date.
•Level 2 Inputs - inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly.
•Level 3 Inputs - unobservable inputs for the asset or liability.
Recurring Fair Value Measurements
As of June 30, 2026
Level 1
Level 2
Level 3
Total
ASSETS:
Cash equivalents$320.4 $— $— $320.4 
Trust assets(1)
0.2 — — 0.2 
Derivative instruments— 9.6 — 9.6 
TOTAL$320.6 $9.6 $— $330.2 
LIABILITIES:
Derivative instruments$— $83.3 $— $83.3 
TOTAL$— $83.3 $— $83.3 

Recurring Fair Value Measurements
As of December 31, 2025
Level 1
Level 2
Level 3
Total
ASSETS:
Cash equivalents$122.3 $— $— $122.3 
Trust assets(1)
0.1 — — 0.1 
Derivative instruments— 1.9 — 1.9 
TOTAL$122.4 $1.9 $— $124.3 
LIABILITIES:
Derivative instruments$— $66.0 $— $66.0 
TOTAL$— $66.0 $— $66.0 
(1)Trust assets are currently invested in money market funds. These trust assets are held to fund the non-qualified supplemental executive pension benefit obligations for certain of our officers.
The following section describes the valuation techniques or inputs for fair value measurements categorized within Level 2 of the fair value hierarchy:
Level 2 Fair Value Measurements:
Asset / LiabilityValuation TechniquesInputs
LME forward financial sales contractsDiscounted cash flowsQuoted LME forward market, Secured Overnight Financing Rate ("SOFR") discount rate
Midwest Premium ("MWP") forward financial sales contractsDiscounted cash flowsQuoted MWP forward market, SOFR discount rate
Fixed for floating swapsDiscounted cash flowsQuoted LME forward market, quoted MWP forward market
Indiana Hub power price swapsDiscounted cash flowsQuoted Indiana Hub forward market, SOFR discount rate
Heavy Fuel Oil ("HFO") price swapsDiscounted cash flowsQuoted HFO forward market
When valuing Level 3 assets and liabilities, we use certain significant unobservable inputs. Management incorporates various inputs and assumptions including forward commodity prices, commodity price volatility and macroeconomic conditions, including interest rates and discount rates. Our estimates of significant unobservable inputs are ultimately based on our estimates of risks that market participants would consider when valuing our assets and liabilities.
During the three and six months ended June 30, 2026 and 2025, there were no Level 3 assets and liabilities measured at fair value on a recurring basis.
We measured the Minority Interest and the Put Option as a single unit of account at fair value as of February 2, 2026, the date of acquisition. The investment is categorized within Level 3 of the fair value hierarchy and was valued at $97.0 million using a sales comparison approach and a probability-weighted scenario approach incorporating a Black-Scholes option pricing model. The valuation considered multiple scenarios based on the timing of successful commencement of the data center’s operations, as well as a scenario in which the conditions to exercise the Put Option are not met.. See Note 4. Sale of Hawesville for additional information on the acquisition of the Minority Interest and Put Option.
The following table describes the significant unobservable inputs used in the valuation.
February 2, 2026
Sales comparison approach
Adjusted price per megawatt
$0.4 - $0.6
Scenario-based approach with the Black-Scholes option pricing model
Discount rate
7.45% - 7.64%
Expected term (years)
3 - 5
Equity volatility
108% - 117%
Dividend yield— %