Business Segments

3 Months Ended

Mar. 31, 2026

Segment Reporting [Abstract]

Business Segments

15.    Business Segments

The Company is a producer of primary aluminum and alumina. The Company has organized itself, including management personnel and systems, financial processes, operational execution, governance and risk oversight, regulatory compliance, and every other aspect of the Company’s operations, to assess and manage the business on a holistic basis, from mine to metal, which tracks the upstream manufacturing process for aluminum. The Company’s Chief Executive Officer and Chief Operating Decision Maker ("CODM") regularly receives and reviews financial information at the consolidated level to evaluate business performance and make operating decisions. The CODM uses the U.S. GAAP measure of consolidated Net Income to develop forecasting, to evaluate the Company’s overall profitability and financial performance and to make key operating decisions, such as the allocation of resources.

Neither the Company's three smelters nor Jamalco’s mining and refining operations meet the definition of operating segments. As a result, the Company has determined that it has only one operating and only one reportable segment, and that segment is managed on a consolidated basis. In accordance with ASC 280-10-50-34, the corresponding information for earlier periods is recast in the tables below to conform with the updated presentation.

Segment assets are reported on our Consolidated Balance Sheets as Total assets. Our Consolidated Statements of Cash Flows presents Depreciation, depletion and amortization expense and includes the measure of capital expenditures as Purchase of property, plant and equipment.

The following table presents information about the Company's single segment for the three months ended March 31, 2026 and 2025.

	Three months ended March 31,
	2026		2025
Net sales	$	649.2	$	633.9
Segment Cost of goods sold(1),(2)	(537.1)		(574.8)
IRA Section 45X tax credit(1),(3)	25.0		19.9
Lower of cost or NRV inventory adjustment(1),(4)	3.3		3.1
Property and equipment expense(1),(5)	(21.6)		(24.8)
Selling, general and administrative expenses	(25.8)		(12.5)
Gain on the sale of Hawesville	287.9		—
Other operating expenses - net	(6.9)		(2.0)
Interest expense - nonaffiliates	(9.9)		(10.0)
Interest expense - affiliates	(0.6)		(1.8)
Interest income	3.1		1.8
Net loss on forward and derivative contracts - nonaffiliates	(65.3)		(5.4)
Gain on insurance proceeds - net	33.0		—
Other loss - net	(5.5)		(3.4)
Income tax expense	(1.8)		(1.6)
Net income	$	327.0	$	22.4

(1)Indicates a component of Cost of goods sold.

(2)Includes raw materials, labor, energy, freight costs, FIFO inventory adjustments and other direct cost of goods sold.

(3)Advanced production credit related to Section 45X of the IRA.

(4)Includes inventory revaluation to lower of cost or net realizable value and changes in inventory reserve.

(5)Represents the depreciation expenses and expenses related to leased assets that are directly related to the cost of goods sold.