10-Q

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q

☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the quarterly period ended June 30, 2026

☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from __________ to __________

Commission File Number: 1-09447

KAISER ALUMINUM CORPORATION

(Exact name of registrant as specified in its charter)

Delaware	94-3030279
(State of incorporation)	(I.R.S. Employer Identification No.)

1550 West McEwen Drive, Suite 500
Franklin, Tennessee	37067
(Address of principal executive offices)	(Zip Code)

(629) 252-7040

(Registrant’s telephone number, including area code)

(Former name, former address and former fiscal year, if changed since last report)

Securities registered pursuant to Section 12(b) of the Act:

Title of each class	Trading symbol	Name of each exchange on which registered
Common stock, par value $0.01 per share	KALU	Nasdaq Global Select Market

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months, and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☒ No ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

Large accelerated filer	☒	Accelerated filer	☐
Non-accelerated filer	☐	Smaller reporting company	☐
		Emerging growth company	☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No ☒

As of July 20, 2026, there were 16,349,092 shares of common stock of the registrant outstanding.

COMMONLY USED OR DEFINED TERMS

Term	Definition
Adjusted EBITDA	Earnings before interest, taxes, depreciation and amortization adjusted for non-run-rate items
Aero/HS Products	2000, 7000 and certain 6000 series alloy products used in the Aerospace, Defense, Space and other end markets requiring high strength applications
Alloy(s)	Certain metals such as copper, zinc, magnesium, manganese and silicon added to primary aluminum to obtain certain attributes
AOCI	Accumulated other comprehensive income (loss)
ASC	Accounting Standards Codification
ASU	Accounting Standards Update
Automotive Extrusions	6000 series extruded aluminum products used in automotive applications
COGS	Cost of products sold, excluding depreciation and amortization
Form 10-Q	This Quarterly Report on Form 10-Q
GAAP	United States Generally Accepted Accounting Principles
GE Products	6000 series alloy products used in the General Engineering end markets
LME	London Metal Exchange
Metal Price Lag	Management’s estimate of the financial impact resulting from the timing difference between aluminum prices included within Hedged Cost of Alloyed Metal and the weighted average market price for aluminum during the period, based on MWTP (defined below), multiplied by our shipment volume during the periods. Metal Price Lag will generally increase our earnings in times of rising primary aluminum prices and decrease our earnings in times of declining primary aluminum prices.
MWP	Midwest Premium, representing the premium over the LME price for primary aluminum in the U.S. Midwest market
MWTP	Midwest Transaction Price, equal to the LME aluminum price plus the MWP (as defined above)
Newark	Kaiser Aluminum manufacturing facility located in Heath, Ohio, a suburb of Newark, Ohio
OPEB	Other Post Employment Benefits
Packaging	3000 and 5000 series alloy products used in the beverage and food packaging end markets
Revolving Credit Facility	Revolving credit facility with Wells Fargo Bank, National Association, as administrative agent, and the other financial institutions party thereto
Salaried VEBA	Salaried Voluntary Employees' Beneficiary Association
SEC	U.S. Securities and Exchange Commission
Senior Notes	Collectively, the fixed-rate unsecured notes we issued during the years ended December 31, 2021 and 2025 at the following interest rates and aggregate principal amounts, respectively: (i) 4.50% and $550.0 million (issued in 2021 and maturing in 2031); and (ii) 5.875% and $500.0 million (issued in 2025 and maturing in 2034)
SOFR	Secured Overnight Financing Rate
Trentwood	Kaiser Aluminum manufacturing facility located in Spokane Valley, Washington
Warrick	Kaiser Aluminum manufacturing facility located in Newburgh, Indiana, in the county of Warrick

TABLE OF CONTENTS

PART I
Item 1. Financial Statements	1
Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations	22
Item 3. Quantitative and Qualitative Disclosures About Market Risk	31
Item 4. Controls and Procedures	32
PART II
Item 1. Legal Proceedings	33
Item 1A. Risk Factors	33
Item 2. Unregistered Sales of Equity Securities and Use of Proceeds	33
Item 3. Defaults Upon Senior Securities	33
Item 4. Mine Safety Disclosures	33
Item 5. Other Information	33
Item 6. Exhibits	34
SIGNATURES	35

KAISER ALUMINUM CORPORATION AND SUBSIDIARY COMPANIES

PART I – FINANCIAL INFORMATION

Item 1. Financial Statements

CONSOLIDATED BALANCE SHEETS (UNAUDITED)

	As of June 30, 2026			As of December 31, 2025
	(In millions of dollars, except share and per share amounts)
ASSETS
Current assets:
Cash and cash equivalents	$	58.5		$	7.0
Receivables, net		575.0			423.3
Contract assets		72.3			63.4
Inventories		848.1			725.2
Prepaid expenses and other current assets		47.9			42.6
Total current assets		1,601.8			1,261.5
Property, plant and equipment, net		1,143.7			1,145.2
Operating lease assets		23.3			22.4
Deferred tax assets, net		—			0.2
Intangible assets, net		38.7			41.0
Goodwill		18.8			18.8
Other assets		83.3			75.7
Total assets	$	2,909.6		$	2,564.8
LIABILITIES AND STOCKHOLDERS’ EQUITY
Current liabilities:
Accounts payable	$	507.2		$	274.6
Accrued salaries, wages and related expenses		53.6			61.3
Other accrued liabilities		81.1			91.3
Total current liabilities		641.9			427.2
Long-term portion of operating lease liabilities		21.4			21.7
Pension and OPEB		72.3			73.4
Deferred tax liabilities		106.6			75.4
Long-term liabilities		85.3			81.4
Long-term debt, net		1,038.3			1,059.6
Total liabilities		1,965.8			1,738.7
Commitments and contingencies – Note 6
Stockholders’ equity:
Preferred stock, 5,000,000 shares authorized at both June 30, 2026 and    December 31, 2025; no shares were issued and outstanding at    June 30, 2026 and December 31, 2025		—			—
Common stock, par value $0.01, 90,000,000 shares authorized at both    June 30, 2026 and December 31, 2025; 23,184,378 shares issued and    16,349,092 shares outstanding at June 30, 2026; 23,045,729 shares    issued and 16,210,443 shares outstanding at December 31, 2025		0.2			0.2
Additional paid in capital		1,134.4			1,132.5
Retained earnings		275.4			142.5
Treasury stock, at cost, 6,835,286 shares at both June 30, 2026 and    December 31, 2025		(475.9	)		(475.9	)
AOCI		9.7			26.8
Total stockholders’ equity		943.8			826.1
Total liabilities and stockholders' equity	$	2,909.6		$	2,564.8

The accompanying notes to interim consolidated financial statements are an integral part of these statements.

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KAISER ALUMINUM CORPORATION AND SUBSIDIARY COMPANIES

STATEMENTS OF CONSOLIDATED INCOME (UNAUDITED)

	Quarter Ended June 30,						Six Months Ended June 30,
	2026			2025			2026			2025
	(In millions of dollars, except share and per share amounts)
Net sales	$	1,256.6		$	823.1		$	2,363.4		$	1,600.5
Costs and expenses:
Cost of products sold, excluding depreciation and amortization		1,057.6			722.8			2,000.8			1,396.2
Depreciation and amortization		29.6			29.6			60.0			59.6
Selling, general, administrative, research and development		35.7			32.6			71.1			63.4
Restructuring costs		—			0.1			—			1.9
Total costs and expenses		1,122.9			785.1			2,131.9			1,521.1
Operating income		133.7			38.0			231.5			79.4
Other (expense) income:
Interest expense		(14.5	)		(12.5	)		(28.9	)		(23.7	)
Other income, net – Note 8		7.1			4.4			6.1			3.0
Income before income taxes		126.3			29.9			208.7			58.7
Income tax provision		(29.5	)		(6.7	)		(49.4	)		(13.9	)
Net income	$	96.8		$	23.2		$	159.3		$	44.8
Net income per common share:
Basic	$	5.92		$	1.44		$	9.77		$	2.77
Diluted	$	5.72		$	1.41		$	9.43		$	2.72
Weighted-average number of common shares outstanding (in thousands):
Basic		16,343			16,160			16,296			16,138
Diluted		16,918			16,479			16,886			16,457

The accompanying notes to interim consolidated financial statements are an integral part of these statements.

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KAISER ALUMINUM CORPORATION AND SUBSIDIARY COMPANIES

STATEMENTS OF CONSOLIDATED COMPREHENSIVE INCOME (UNAUDITED)

	Quarter Ended June 30,					Six Months Ended June 30,
	2026			2025		2026			2025
	(In millions of dollars)
Net income	$	96.8		$	23.2	$	159.3		$	44.8
Other comprehensive income (loss), net of tax – Note 7:
Defined benefit plans		0.2			0.4		0.4			0.5
Cash flow hedges		(22.5	)		3.7		(17.5	)		6.2
Other comprehensive (loss) income, net of tax		(22.3	)		4.1		(17.1	)		6.7
Comprehensive income	$	74.5		$	27.3	$	142.2		$	51.5

The accompanying notes to interim consolidated financial statements are an integral part of these statements.

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KAISER ALUMINUM CORPORATION AND SUBSIDIARY COMPANIES

STATEMENTS OF CONSOLIDATED STOCKHOLDERS’ EQUITY (UNAUDITED)

Six Months Ended June 30, 2026

	Common Shares Outstanding1			Common Stock		Additional Paid in Capital			Retained Earnings			Treasury Stock			AOCI			Total
	(In millions of dollars, except share and per share amounts)
BALANCE, December 31, 2025		16,210,443		$	0.2	$	1,132.5		$	142.5		$	(475.9	)	$	26.8		$	826.1
Net income		—			—		—			62.5			—			—			62.5
Other comprehensive income, net of tax		—			—		—			—			—			5.2			5.2
Common shares issued (including impacts from    Long-Term Incentive programs)		199,737			—		—			—			—			—			—
Cancellation of shares to cover tax withholdings    upon common shares issued		(70,056	)		—		(8.8	)		—			—			—			(8.8	)
Cash dividends declared2		—			—		—			(13.6	)		—			—			(13.6	)
Amortization of unearned equity compensation		—			—		5.9			—			—			—			5.9
BALANCE, March 31, 2026		16,340,124		$	0.2	$	1,129.6		$	191.4		$	(475.9	)	$	32.0		$	877.3
Net income		—			—		—			96.8			—			—			96.8
Other comprehensive loss, net of tax		—			—		—			—			—			(22.3	)		(22.3	)
Common shares issued (including impacts from    Long-Term Incentive programs)		9,230			—		0.4			—			—			—			0.4
Cancellation of shares to cover tax withholdings    upon common shares issued		(262	)		—		(0.1	)		—			—			—			(0.1	)
Cash dividends declared2		—			—		—			(12.8	)		—			—			(12.8	)
Amortization of unearned equity compensation		—			—		4.5			—			—			—			4.5
BALANCE, June 30, 2026		16,349,092		$	0.2	$	1,134.4		$	275.4		$	(475.9	)	$	9.7		$	943.8

1.At June 30, 2026, 787,950 shares were available for awards under the Kaiser Aluminum Corporation 2021 Equity and Incentive Compensation Plan, as amended and restated.

2.Dividends declared per common share were $0.77 for the quarters ended March 31, 2026 and June 30, 2026.

The accompanying notes to interim consolidated financial statements are an integral part of these statements.

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KAISER ALUMINUM CORPORATION AND SUBSIDIARY COMPANIES

STATEMENTS OF CONSOLIDATED STOCKHOLDERS’ EQUITY CONTINUED (UNAUDITED)

Six Months Ended June 30, 2025

	Common Shares Outstanding			Common Stock		Additional Paid in Capital			Retained Earnings			Treasury Stock			AOCI		Total
	(In millions of dollars, except share and per share amounts)
BALANCE, December 31, 2024		16,095,898		$	0.2	$	1,117.0		$	81.3		$	(475.9	)	$	20.5	$	743.1
Net income		—			—		—			21.6			—			—		21.6
Other comprehensive income, net of tax		—			—		—			—			—			2.6		2.6
Common shares issued (including impacts from    Long-Term Incentive programs)		84,115			—		—			—			—			—		—
Cancellation of shares to cover tax withholdings    upon common shares issued		(25,637	)		—		(1.8	)		—			—			—		(1.8	)
Cash dividends declared1		—			—		—			(12.9	)		—			—		(12.9	)
Amortization of unearned equity compensation		—			—		4.2			—			—			—		4.2
BALANCE, March 31, 2025		16,154,376		$	0.2	$	1,119.4		$	90.0		$	(475.9	)	$	23.1	$	756.8
Net income		—			—		—			23.2			—			—		23.2
Other comprehensive income, net of tax		—			—		—			—			—			4.1		4.1
Common shares issued (including impacts from    Long-Term Incentive programs)		23,582			—		0.4			—			—			—		0.4
Cancellation of shares to cover tax withholdings    upon common shares issued		(219	)		—		—			—			—			—		—
Cash dividends declared1		—			—		—			(12.8	)		—			—		(12.8	)
Amortization of unearned equity compensation		—			—		4.3			—			—			—		4.3
BALANCE, June 30, 2025		16,177,739		$	0.2	$	1,124.1		$	100.4		$	(475.9	)	$	27.2	$	776.0

1.Dividends declared per common share were $0.77 for the quarters ended March 31, 2025 and June 30, 2025.

The accompanying notes to interim consolidated financial statements are an integral part of these statements.

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KAISER ALUMINUM CORPORATION AND SUBSIDIARY COMPANIES

STATEMENTS OF CONSOLIDATED CASH FLOWS (UNAUDITED)

	Six Months Ended June 30,
	2026			2025
	(In millions of dollars)
Cash flows from operating activities1:
Net income	$	159.3		$	44.8
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation of property, plant and equipment		57.8			57.3
Amortization of definite-lived intangible assets		2.2			2.3
Amortization of debt issuance costs		1.3			1.1
Deferred income taxes		36.6			11.2
Non-cash equity compensation		10.8			8.9
Non-cash asset impairment charge		0.7			—
(Gain) loss on disposition of property, plant and equipment		(4.3	)		1.0
Bad debt expense		0.1			—
Non-cash postretirement and postemployment defined benefit plan cost		4.2			4.8
Changes in operating assets and liabilities:
Receivables		(151.8	)		(75.9	)
Contract assets		(8.9	)		4.3
Inventories		(123.6	)		6.3
Prepaid expenses and other current assets		(10.8	)		(6.7	)
Accounts payable		229.0			45.7
Accrued liabilities		(48.8	)		(26.0	)
Annual variable cash contributions to Salaried VEBA		(2.9	)		(0.7	)
Long-term assets and liabilities, net		(3.5	)		(5.5	)
Net cash provided by operating activities		147.4			72.9
Cash flows from investing activities1:
Capital expenditures		(43.8	)		(81.8	)
Purchase of equity securities		(0.5	)		(0.4	)
Proceeds from sale of equity securities		—			0.1
Proceeds from disposition of property, plant and equipment		7.6			0.2
Net cash used in investing activities		(36.7	)		(81.9	)
Cash flows from financing activities1:
Borrowings under the Revolving Credit Facility		397.8			217.6
Repayment of borrowings under the Revolving Credit Facility		(420.1	)		(184.8	)
Repayment of finance lease		(1.6	)		(1.3	)
Cancellation of shares to cover tax withholdings upon common shares issued		(8.9	)		(1.8	)
Cash dividends and dividend equivalents paid		(26.4	)		(25.7	)
Net cash (used in) provided by financing activities		(59.2	)		4.0
Net increase (decrease) in cash, cash equivalents and restricted cash during the period		51.5			(5.0	)
Cash, cash equivalents and restricted cash at beginning of period		26.9			37.9
Cash, cash equivalents and restricted cash at end of period	$	78.4		$	32.9

1.See Note 11 for supplemental cash flow information.

The accompanying notes to interim consolidated financial statements are an integral part of these statements.

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KAISER ALUMINUM CORPORATION AND SUBSIDIARY COMPANIES

NOTES TO INTERIM CONSOLIDATED FINANCIAL STATEMENTS - UNAUDITED

NOTES INDEX

Note 1	Basis of Presentation and Recent Accounting Pronouncements	8
Note 2	Supplemental Balance Sheet Information	10
Note 3	Employee Benefits	11
Note 4	Derivatives, Hedging Programs and Other Financial Instruments	12
Note 5	Debt and Credit Facility	14
Note 6	Commitments and Contingencies	15
Note 7	Accumulated Other Comprehensive Income	17
Note 8	Other Income, Net	17
Note 9	Income Tax Matters	18
Note 10	Earnings Per Share	18
Note 11	Supplemental Cash Flow Information	19
Note 12	Business, Product, and Geographical Area Information	20
Note 13	Subsequent Events	21

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KAISER ALUMINUM CORPORATION AND SUBSIDIARY COMPANIES

NOTES TO INTERIM CONSOLIDATED FINANCIAL STATEMENTS – UNAUDITED

1. Basis of Presentation and Recent Accounting Pronouncements

This Form 10-Q should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2025. Unless the context otherwise requires, references in these notes to interim consolidated financial statements - unaudited to “Kaiser,” “we,” “us,” “our,” “the Company” and “our Company” refer collectively to Kaiser Aluminum Corporation and its subsidiaries.

Principles of Consolidation and Basis of Presentation. The accompanying unaudited consolidated financial statements include the accounts of our wholly owned subsidiaries and are prepared in accordance with GAAP and the rules and regulations of the SEC applicable for interim periods and, therefore, do not include all information and footnotes required by GAAP for complete financial statements. In management’s opinion, all adjustments (which include normal recurring adjustments) considered necessary for a fair presentation have been included. We have reclassified certain items in prior periods to conform to current classifications. The results of operations for our interim periods are not necessarily indicative of the results of operations that may be achieved for the entire 2026 fiscal year. The financial information as of December 31, 2025 is derived from our audited consolidated financial statements and footnotes included in our Annual Report on Form 10-K for the year ended December 31, 2025. Tables throughout this document are presented in millions of United States (“U.S.”) dollars unless otherwise stated, except for per share amounts which are presented in U.S. dollars.

Use of Estimates in the Preparation of Financial Statements. The preparation of financial statements in accordance with GAAP requires the use of estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities known to exist as of the date the financial statements are published and the reported amounts of revenues and expenses during the reporting period. Uncertainties with respect to such estimates and assumptions are inherent in the preparation of our consolidated financial statements; accordingly, it is possible that the actual results could differ from these estimates and assumptions, which could have a material effect on the reported amounts of our consolidated financial position and results of operations.

Adoption of New Accounting Pronouncements

Government Grants. In December 2025, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2025-10 (“ASU 2025-10”), Government Grants (Topic 832): Accounting for Government Grants Received by Business Entities, to establish authoritative guidance on the accounting for government grants received by business entities. We early adopted ASU 2025-10 during the quarter ended June 30, 2026, using the full retrospective transition method. The adoption of ASU 2025-10 did not have a material impact on our consolidated financial statements for all periods presented.

Accounting Pronouncements Issued But Not Yet Adopted

Disclosure Improvements. In October 2023, the FASB issued ASU No. 2023-06 (“ASU 2023-06”), Codification Amendments in Response to the SEC’s Disclosure Update and Simplification Initiative. The guidance amends GAAP to reflect updates and simplifications to certain disclosure requirements referred to the FASB by the SEC. The amendments in ASU 2023-06 will become effective on the date which the SEC’s removal of the related disclosure becomes effective. If by June 30, 2027, the SEC does not remove the related disclosure, the pending amendment will be removed from ASC 2023-06 and it will not be effective. Adoption of ASU 2023-06 is expected to modify the disclosure and presentation requirements only and is not expected to have a material impact on our consolidated financial statements.

Disaggregation of Income Statement Expenses. In November 2024, the FASB issued ASU No. 2024-03 (“ASU 2024-03”), Disaggregation of Income Statement Expenses. The guidance requires additional, disaggregated disclosure about certain income statement expense line items. The amendments in ASU 2024-03 are effective for annual reporting periods beginning after December 15, 2026 and interim reporting periods beginning after December 15, 2027, with early adoption permitted, and is required to be applied prospectively with the option of retrospective application. We plan to adopt the provisions of ASU 2024-03 prospectively in the fourth quarter of fiscal 2027 and continue to evaluate the disclosure requirements related to the new standard.

Hedge Accounting Improvements. In November 2025, the FASB issued ASU No. 2025-09 (“ASU 2025-09”), Derivatives and Hedging (Topic 815): Hedge Accounting Improvements. The guidance introduces targeted refinements intended to improve the operability of hedge accounting and better align financial reporting with risk management activities, including greater flexibility in hedge designation and clarifications for certain instruments. ASU 2025-09 is effective for fiscal years beginning after December 15,

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KAISER ALUMINUM CORPORATION AND SUBSIDIARY COMPANIES

NOTES TO INTERIM CONSOLIDATED FINANCIAL STATEMENTS – UNAUDITED

2026, with early adoption permitted. We are currently evaluating the impact of this pronouncement on our consolidated financial statements.

Interim Reporting Narrow-Scope Improvements. In December 2025, the FASB issued ASU No. 2025-11 (“ASU 2025-11”), Interim Reporting (Topic 270): Narrow-Scope Improvements, which clarifies the scope, form and content, and required disclosures in interim financial statements prepared under GAAP. ASU 2025-11 enhances guidance for entities that issue condensed interim statements and reinstates a principles-based requirement to disclose material events since the last annual period. ASU 2025-11 is effective for interim periods in fiscal years beginning after December 15, 2027, with early adoption permitted and retrospective application optional. We are currently evaluating the impact of this pronouncement on our consolidated financial statements.

Environmental Credit Programs. In May 2026, the FASB issued ASU No. 2026-02 (“ASU 2026-02”), Environmental Credits and Environmental Credit Obligations (Topic 818), which introduces a comprehensive model that establishes recognition, measurement, presentation, and disclosure requirements for environmental credits and, when applicable, compliance obligations that may be settled by using environmental credits. ASU 2026-02 is effective for annual reporting periods beginning after December 15, 2027, and interim reporting periods within those annual reporting periods, with early adoption permitted. ASU 2026-02 is required to be applied on a retrospective basis through a cumulative-effect adjustment to retained earnings as of the beginning of the period of adoption. We are currently evaluating the impact of this pronouncement on our consolidated financial statements.

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KAISER ALUMINUM CORPORATION AND SUBSIDIARY COMPANIES

NOTES TO INTERIM CONSOLIDATED FINANCIAL STATEMENTS – UNAUDITED

2. Supplemental Balance Sheet Information

	As of June 30, 2026			As of December 31, 2025
Receivables, Net
Accounts receivable	$	575.6		$	423.9
Allowance for doubtful receivables		(0.6	)		(0.6	)
Receivables, net	$	575.0		$	423.3
Inventories
Finished products	$	145.7		$	156.1
Work-in-process		364.7			316.7
Raw materials		321.8			236.2
Operating supplies		15.9			16.2
Inventories	$	848.1		$	725.2
Property, Plant and Equipment, Net
Land and improvements	$	45.8		$	38.2
Buildings and leasehold improvements		306.4			302.6
Machinery and equipment		1,610.3			1,586.7
Construction in progress		84.6			66.7
Property, plant and equipment, gross		2,047.1			1,994.2
Accumulated depreciation and amortization		(903.4	)		(849.1	)
Land held for sale	—				0.1
Property, plant and equipment, net	$	1,143.7		$	1,145.2
Other Assets
Restricted cash – Note 11	$	19.9		$	19.9
Long-term replacement parts		34.0			28.5
Net assets of Salaried VEBA		10.0			9.7
Other		19.4			17.6
Other assets	$	83.3		$	75.7
.
Other Accrued Liabilities
Uncleared cash disbursements	$	0.5		$	45.8
Accrued income taxes and other taxes payable		8.5			7.8
Accrued annual contribution to Salaried VEBA	—				2.9
Accrued interest		12.0			6.9
Current operating lease liabilities		5.7			4.8
Current finance lease liabilities		3.5			2.3
Current deferred compensation plan liabilities – Note 3		1.3			1.2
Other – Note 4		49.6			19.6
Other accrued liabilities	$	81.1		$	91.3
Long-Term Liabilities
Workers' compensation accrual	$	25.9		$	26.0
Long-term environmental accrual – Note 6		16.7			17.4
Other long-term liabilities		42.7			38.0
Long-term liabilities	$	85.3		$	81.4

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NOTES TO INTERIM CONSOLIDATED FINANCIAL STATEMENTS – UNAUDITED

3. Employee Benefits

Deferred Compensation Plan

Assets of our deferred compensation plan are included in Other assets. Such assets, representing diversified investment funds in registered investment companies, are classified within Level 1 of the fair value hierarchy and are measured and recorded at fair value based on their quoted market prices. These assets are accounted for as equity investments, with changes in fair value recorded within Other income, net (see Note 8). Offsetting liabilities relating to the deferred compensation plan are included in Other accrued liabilities and Long-term liabilities.

Short-Term Incentive Plans

As of June 30, 2026, we had a liability of $18.7 million recorded within Accrued salaries, wages and related expenses for estimated probable future payments under the 2026 short-term incentive plans.

Postretirement and Postemployment Benefit Plans

The following table presents the total expense related to all postretirement and postemployment benefit plans:

	Quarter Ended June 30,				Six Months Ended June 30,
	2026		2025		2026		2025
Defined contribution plans1	$	4.5	$	4.6	$	10.5	$	10.6
Deferred compensation plan2		0.9		0.4		1.0		0.6
Multiemployer pension plans1		1.6		1.6		3.1		3.1
Net periodic postretirement and postemployment benefit cost relating to defined benefit plans3		2.1		2.5		4.2		4.8
Total	$	9.1	$	9.1	$	18.8	$	19.1

1.Substantially all of these charges related to employee benefits are in COGS with the remaining balance in Selling, general, administrative, research, and development (“SG&A and R&D”) in our Statements of Consolidated Income.

2.Deferred compensation plan expense is included within SG&A and R&D in our Statements of Consolidated Income.

3.The current service cost component of Net periodic postretirement and postemployment benefit cost relating to both the pension plans and the OPEB plan is included within COGS in our Statements of Consolidated Income for all periods presented. All other components are included within Other income, net, in our Statements of Consolidated Income.

Components of Net Periodic Postretirement and Postemployment Benefit Cost. The following tables present the components of Net periodic postretirement and postemployment benefit cost relating to our defined benefit plans:

	Pension Plans						OPEB						Salaried VEBA
	Quarter Ended June 30,						Quarter Ended June 30,						Quarter Ended June 30,
	2026			2025			2026			2025			2026			2025
Service cost	$	0.9		$	0.8		$	0.2		$	0.3		$	—		$	—
Interest cost		0.5			0.4			0.9			0.8			0.4			0.6
Expected return on plan assets		(0.5	)		(0.3	)		—			—			(0.6	)		(0.6	)
Amortization of prior service cost1		0.2			0.2			—			—			0.7			0.8
Amortization of net actuarial gain		—			—			(0.3	)		(0.4	)		(0.3	)		(0.1	)
Total net periodic postretirement and postemployment benefit cost	$	1.1		$	1.1		$	0.8		$	0.7		$	0.2		$	0.7

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NOTES TO INTERIM CONSOLIDATED FINANCIAL STATEMENTS – UNAUDITED

	Pension Plans						OPEB						Salaried VEBA
	Six Months Ended June 30,						Six Months Ended June 30,						Six Months Ended June 30,
	2026			2025			2026			2025			2026			2025
Service cost	$	1.7		$	1.7		$	0.4		$	0.5		$	—		$	—
Interest cost		1.0			0.8			1.8			1.7			0.9			1.1
Expected return on plan assets		(1.0	)		(0.7	)		—			—			(1.2	)		(1.1	)
Amortization of prior service cost1		0.4			0.4			—			—			1.4			1.5
Amortization of net actuarial gain		—			—			(0.6	)		(0.9	)		(0.6	)		(0.2	)
Total net periodic postretirement and postemployment benefit cost	$	2.1		$	2.2		$	1.6		$	1.3		$	0.5		$	1.3

1.We amortize prior service cost on a straight-line basis over the average remaining years of service of the active plan participants.

4. Derivatives, Hedging Programs and Other Financial Instruments

Overview

We utilize derivative instruments to manage exposure to: (i) metal price risk related to aluminum and certain alloys used as raw material for our fabrication operations; (ii) energy price risk related to natural gas and electricity used in our production processes; and (iii) foreign currency exchange rate risk related to certain equipment and service agreements. We do not use derivative financial instruments for trading or other speculative purposes. Hedging transactions are executed centrally and are overseen by a committee (“Hedging Committee”) composed of key operations and finance personnel from the management team. Management reviews the scope of the Hedging Committee’s activities with our Board of Directors.

We are exposed to counterparty credit risk on all of our derivative instruments. Our counterparties are major investment-grade financial institutions or trading companies, and our hedging transactions are governed by negotiated International Swaps and Derivatives Association Master Agreements, which generally require collateral to be posted by our counterparties above specified credit thresholds, which may adjust up or down based on changes in counterparty credit ratings. As a result, we believe the risk of loss is remote and contained. The aggregate fair value of our derivative instruments that were in a net liability position was $19.2 million and $0.1 million at June 30, 2026 and December 31, 2025, respectively, and we had no collateral posted as of those dates.

In addition, our firm-price customer sales commitments create incremental customer credit risk related to metal price movements. Under certain circumstances, we mitigate this risk by periodically requiring cash collateral to be posted by our customers, which we classify as deferred revenue and include as a component of Other accrued liabilities. We had $0.2 million of cash collateral posted by our customers at June 30, 2026 compared to no cash collateral posted by our customers at December 31, 2025.

The above described derivative instruments are typically designated as cash flow hedges. Unrealized gains and losses associated with our cash flow hedges are deferred in Other comprehensive income, net of tax, and reclassified to COGS when such hedges settle or when it is probable that the original forecasted transactions will not occur by the end of the originally specified time period. See Note 7 for the total amount of gain or loss on derivative instruments designated and qualifying as cash flow hedging instruments that was reported in AOCI, as well as the related reclassifications into earnings and tax effects. Cumulative gains and losses related to cash flow hedges are reclassified out of AOCI and recorded within COGS when the associated hedged commodity purchases impact earnings.

From time to time, we enter into commodity and foreign currency forward contracts that are not designated as hedging instruments to mitigate certain short‑term impacts, as identified. The gain or loss on these commodity and foreign currency derivatives is recognized within COGS and Other expense, net, respectively. As of June 30, 2026 and December 31, 2025, we had no outstanding non-designated derivative hedge positions.

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NOTES TO INTERIM CONSOLIDATED FINANCIAL STATEMENTS – UNAUDITED

Notional Amount of Derivative Contracts

The following table summarizes our derivative positions at June 30, 2026:

Aluminum	Maturity Period	Notional Amount of Contracts (mmlbs)
Fixed price purchase contracts for LME	July 2026 through November 2027		82.8
Fixed price sale contracts for LME	July 2026 through April 2027		6.6
Fixed price purchase contracts for MWP	July 2026 through November 2027		82.8
Fixed price sale contracts for MWP	July 2026 through April 2027		6.6

Alloying Metals	Maturity Period	Notional Amount of Contracts (mmlbs)
Fixed price purchase contracts	July 2026 through December 2027		5.2

Natural Gas	Maturity Period	Notional Amount of Contracts (mmbtu)
Fixed price purchase contracts	July 2026 through December 2028		4,260,000

Electricity	Maturity Period	Notional Amount of Contracts (Mwh)
Fixed price purchase contracts	July 2026 through December 2028		369,100

Euro	Maturity Period	Notional Amount of Contracts (in millions of Euros)
Fixed price forward purchase contracts	July 2026 through July 2027	€	0.1

(Gain) Loss on Derivative Contracts

The following table summarizes the amount of (gain) loss on derivative contracts recorded within our Statements of Consolidated Income in COGS:

	Quarter Ended June 30,						Six Months Ended June 30,
	2026			2025			2026			2025
Total of income and expense line items presented in our Statements of Consolidated Income in which the effects of hedges are recorded:
Cash flow hedges	$	1,057.6		$	722.8		$	2,000.8		$	1,396.2
(Gain) loss recognized in our Statements of Consolidated Income related to cash flow hedges:
Aluminum	$	(14.8	)	$	(2.2	)	$	(23.3	)	$	(7.4	)
Alloying Metals		(0.7	)		(0.5	)		(1.2	)		(0.9	)
Natural gas		0.5			0.3			0.2			0.3
Electricity		2.2			—			2.2			—
Foreign exchange contracts		—			(0.1	)		—			—
Total gain recognized in our Statements of Consolidated Income related to cash flow hedges	$	(12.8	)	$	(2.5	)	$	(22.1	)	$	(8.0	)

Fair Values of Derivative Contracts

The fair values of our derivative contracts are based upon trades in liquid markets. Valuation model inputs can be verified, and valuation techniques do not involve significant judgment. The fair values of such derivatives are classified within Level 2 of the fair value hierarchy.

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NOTES TO INTERIM CONSOLIDATED FINANCIAL STATEMENTS – UNAUDITED

All of our derivative contracts with counterparties are subject to enforceable master netting arrangements. We reflect the fair value of our derivative contracts on a gross basis on our Consolidated Balance Sheets. The following table presents the fair value of our derivative financial instruments:

	As of June 30, 2026								As of December 31, 2025
	Assets		Liabilities			Net Amount			Assets		Liabilities			Net Amount
Cash Flow Hedges:
Aluminum –
Fixed price purchase contracts for LME	$	0.4	$	(12.6	)	$	(12.2	)	$	2.6	$	—		$	2.6
Fixed price sale contracts for LME		0.3		—			0.3			—		(0.8	)		(0.8	)
Fixed price purchase contracts for MWP		1.6		(6.4	)		(4.8	)		3.8		(0.1	)		3.7
Fixed price sale contracts for MWP		—		—			—			—		(1.6	)		(1.6	)
Alloying Metals – Fixed price purchase contracts		2.9		—			2.9			2.4		—			2.4
Natural gas – Fixed price purchase contracts		1.0		(2.7	)		(1.7	)		0.7		(1.3	)		(0.6	)
Electricity – Fixed price purchase contracts		1.2		(2.9	)		(1.7	)		—		—			—
Foreign currency – Fixed price forward contracts		—		—			—			0.1		—			0.1
Total	$	7.4	$	(24.6	)	$	(17.2	)	$	9.6	$	(3.8	)	$	5.8

The following table presents the total amounts of derivative assets and liabilities on our Consolidated Balance Sheets:

	As of June 30, 2026			As of December 31, 2025
Derivative assets:
Prepaid expenses and other current assets	$	5.2		$	8.3
Other assets		2.2			1.3
Total derivative assets	$	7.4		$	9.6
Derivative liabilities:
Other accrued liabilities	$	(22.8	)	$	(3.1	)
Long-term liabilities		(1.8	)		(0.7	)
Total derivative liabilities	$	(24.6	)	$	(3.8	)

Fair Values of Other Financial Instruments

All Other Financial Assets and Liabilities. We believe that the fair values of our financial assets and liabilities (accounts receivable, contract assets, current assets, accounts payable, and accrued liabilities) approximate their respective fair values due to their short maturities and nominal credit risk.

5. Debt and Credit Facility

Senior Notes

At June 30, 2026 and December 31, 2025, we had outstanding fixed-rate unsecured Senior Notes with varying maturity dates. The stated interest rates and aggregate principal amounts of such Senior Notes were, respectively: (i) 4.50% and $550.0 million (“4.50% Senior Notes”) and (ii) 5.875% and $500.0 million (“5.875% Senior Notes”). Our Senior Notes do not require us to make any mandatory redemptions or sinking fund payments. The following table summarizes key details of our Senior Notes:

				Outstanding
	Issuance Date	Maturity	Effective Interest Rate	As of June 30, 2026			As of December 31, 2025
4.50% Senior Notes	May 2021	June 2031	4.7%	$	550.0		$	550.0
5.875% Senior Notes	November 2025	March 2034	6.1%		500.0			500.0
Total debt					1,050.0			1,050.0
Unamortized issuance costs					(11.7	)		(12.7	)
Total carrying amount				$	1,038.3		$	1,037.3

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NOTES TO INTERIM CONSOLIDATED FINANCIAL STATEMENTS – UNAUDITED

The following table presents the fair value of our outstanding Senior Notes, which are Level 1 liabilities:

	As of June 30, 2026		As of December 31, 2025
4.50% Senior Notes	$	526.5	$	531.4
5.875% Senior Notes	$	494.8	$	501.6

Revolving Credit Facility

In October 2019, we entered into a Revolving Credit Facility. Joining us as borrowers under the Revolving Credit Facility are four of our wholly owned domestic operating subsidiaries: (i) Kaiser Aluminum Investments Company; (ii) Kaiser Aluminum Fabricated Products, LLC; (iii) Kaiser Aluminum Washington, LLC; and (iv) Kaiser Aluminum Warrick, LLC.

As amended in October 2025, the Revolving Credit Facility is set to mature in October 2030 and contains a maximum commitment amount of $575.0 million (of which up to a maximum of $50.0 million may be utilized for letters of credit). The facility includes an accordion feature that allows for an increase in total revolving commitments of up to $200.0 million, plus an additional amount for a first-in last-out tranche, subject to lender approval and other customary conditions. The amount we can borrow under the Revolving Credit Facility is determined by the value of our eligible accounts receivable and inventory and certain other assets, which serve as collateral for the Revolving Credit Facility. Borrowings under the amended Revolving Credit Facility bear interest at a rate equal to either a base rate or the SOFR, plus, in each case, a specified variable percentage between 125 - 150 basis points for SOFR loans (or 25 - 50 basis points for base rate loans) determined by reference to the then-remaining borrowing availability under the Revolving Credit Facility and, in certain instances, a fixed margin. Outstanding borrowings under the Revolving Credit Facility are reported within Long-term debt, net, on our Consolidated Balance Sheets. We had no outstanding borrowings under the Revolving Credit Facility as of June 30, 2026 and $22.3 million of outstanding borrowings under the Revolving Credit Facility as of December 31, 2025.

The following table summarizes availability and usage of our Revolving Credit Facility as determined by a borrowing base calculated as of June 30, 2026:

Revolving Credit Facility borrowing commitment	$	575.0
Borrowing base availability	$	575.0
Less: Outstanding borrowings under Revolving Credit Facility		—
Less: Outstanding letters of credit under Revolving Credit Facility		(5.1	)
Remaining borrowing availability	$	569.9

Interest Expense

The following table presents interest expense relating to our Senior Notes and Revolving Credit Facility:

	Quarter Ended June 30,						Six Months Ended June 30,
	2026			2025			2026			2025
Senior Notes interest expense, including debt issuance cost amortization	$	14.0		$	12.4		$	28.0		$	24.8
Revolving Credit Facility interest expense, including commitment fees and finance cost amortization		0.7			0.7			1.3			1.3
Interest expense on finance lease liabilities		0.3			0.2			0.5			0.4
Interest expense capitalized as construction in progress		(0.5	)		(0.8	)		(0.9	)		(2.8	)
Total interest expense	$	14.5		$	12.5		$	28.9		$	23.7

6. Commitments and Contingencies

Commitments. We have a variety of financial commitments, including purchase agreements, forward foreign exchange and forward sales contracts, indebtedness and letters of credit (see Note 4 and Note 5).

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NOTES TO INTERIM CONSOLIDATED FINANCIAL STATEMENTS – UNAUDITED

Environmental Contingencies. We are subject to several environmental laws and regulations, potential fines or penalties assessed for alleged breaches of such laws and regulations, and potential claims based upon such laws and regulations. We are also subject to legacy environmental contingencies related to activities that occurred at our operating facilities prior to July 6, 2006, which represent the majority of our environmental accruals of $17.6 million as of June 30, 2026. This accrual represents our undiscounted estimate of costs reasonably expected to be incurred based on current laws and regulations, available facts, existing technologies, and our assessment of the likely remediation actions to be taken.

Based on approved and proposed remediation action plans for the various facilities, we expect that the implementation and ongoing monitoring could occur over a period of 30 or more years. As additional facts are developed, feasibility studies are completed, remediation plans are modified, necessary regulatory approvals for the implementation of remediation are obtained, alternative technologies are developed and/or other factors change, there may be revisions to management’s estimates, and actual costs may exceed the current environmental accruals by up to $14.2 million. Changes to our estimates may occur within the next 12 months as new information becomes available.

Other Contingencies. We are party to various lawsuits, claims, investigations and administrative proceedings that arise in connection with past and current operations. We evaluate such matters on a case-by-case basis and our policy is to vigorously contest any such claims we believe are without merit. We accrue for a legal liability when it is both probable that a liability has been incurred and the amount of the loss is reasonably estimable. Quarterly, in addition to when changes in facts and circumstances require it, we review and adjust these accruals to reflect the impacts of negotiations, settlements, rulings, advice of legal counsel and other information and events pertaining to a particular case. While uncertainties are inherent in the final outcome of such matters and it is presently impossible to determine the actual cost that may ultimately be incurred, we believe that we have sufficiently accrued for such matters and that the ultimate resolution of pending matters will not have a material impact on our consolidated financial position, operating results or liquidity.

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NOTES TO INTERIM CONSOLIDATED FINANCIAL STATEMENTS – UNAUDITED

7. Accumulated Other Comprehensive Income

The following table presents the changes in the accumulated balances for each component of AOCI:

	Quarter Ended June 30,						Six Months Ended June 30,
	2026			2025			2026			2025
Defined Benefit Plans:
Beginning balance	$	22.7		$	19.2		$	22.5		$	19.1
Actuarial loss arising during the period		—			—			—			(0.1	)
Net actuarial loss arising during the period		—			—			—			(0.1	)
Amortization of net actuarial gain1		(0.6	)		(0.5	)		(1.2	)		(1.1	)
Amortization of prior service cost1		0.9			1.0			1.8			1.9
Less: income tax expense2		(0.1	)		(0.1	)		(0.2	)		(0.2	)
Net amortization reclassified from AOCI to Net income		0.2			0.4			0.4			0.6
Other comprehensive income, net of tax		0.2			0.4			0.4			0.5
Ending balance	$	22.9		$	19.6		$	22.9		$	19.6
Cash Flow Hedges:
Beginning balance	$	9.3		$	3.9		$	4.3		$	1.4
Unrealized (loss) gain on cash flow hedges		(16.6	)		7.5			(0.8	)		16.2
Less: income tax benefit (expense)		3.9			(1.8	)		0.2			(3.8	)
Net unrealized (loss) gain on cash flow hedges		(12.7	)		5.7			(0.6	)		12.4
Reclassification of unrealized gain upon settlement of cash flow hedges		(12.8	)		(2.5	)		(22.1	)		(8.0	)
Less: income tax expense2		3.0			0.5			5.2			1.8
Net gain reclassified from AOCI to Net income		(9.8	)		(2.0	)		(16.9	)		(6.2	)
Other comprehensive (loss) income, net of tax		(22.5	)		3.7			(17.5	)		6.2
Ending balance3	$	(13.2	)	$	7.6		$	(13.2	)	$	7.6
Total AOCI ending balance	$	9.7		$	27.2		$	9.7		$	27.2

1.Amounts amortized out of AOCI related to pension and other postretirement and postemployment benefits were included within Net periodic postretirement and postemployment benefit cost (see Note 3).

2.Income tax amounts reclassified out of AOCI were included as a component of Income tax provision.

3.As of June 30, 2026, we estimate a net mark-to-market loss before tax of $17.6 million in AOCI will be reclassified into Net income upon settlement within the next 12 months.

8. Other Income, Net

The following table presents the components of Other income, net:

	Quarter Ended June 30,						Six Months Ended June 30,
	2026			2025			2026			2025
Interest income	$	0.2		$	0.2		$	0.4		$	0.4
Net periodic postretirement and postemployment benefit cost		(1.0	)		(1.4	)		(2.1	)		(2.6	)
Unrealized gain on equity securities		0.2			0.2			—			0.1
Gain on disposition of non-operating property, plant and equipment		7.5			—			7.5			—
Gain on business interruption insurance recoveries1		—			5.0			—			5.0
All other, net		0.2			0.4			0.3			0.1
Other income, net	$	7.1		$	4.4		$	6.1		$	3.0

1.Represents insurance settlement proceeds related to business interruption claims. Such proceeds are recognized in the period in which they are received or become realizable.

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NOTES TO INTERIM CONSOLIDATED FINANCIAL STATEMENTS – UNAUDITED

Supply Chain Financing. We are party to several supply chain financing arrangements, in which we may sell certain of our customers’ trade accounts receivable to such customers’ financial institutions without recourse. During the quarter and six months ended June 30, 2026 we sold trade accounts receivable totaling $334.3 million and $629.5 million, respectively, related to these supply chain financing arrangements, of which our customers’ financial institutions applied discount fees totaling $7.7 million and $14.2 million, respectively. During the quarter and six months ended June 30, 2025, we sold trade accounts receivable totaling $214.2 million and $484.2 million, respectively, related to these supply chain financing arrangements, of which our customers’ financial institutions applied discount fees totaling $5.4 million and $11.0 million, respectively. To the extent discount fees related to the sale of trade accounts receivable under supply chain financing arrangements are not reimbursed by our customers, they are included in Other income, net. As of June 30, 2026, we had been and/or expected to be substantially reimbursed by our customers for these discount fees, in accordance with the underlying sales agreements.

9. Income Tax Matters

The following table presents the income tax provision by region:

	Quarter Ended June 30,						Six Months Ended June 30,
	2026			2025			2026			2025
Domestic	$	(28.9	)	$	(6.0	)	$	(48.2	)	$	(12.6	)
Foreign		(0.6	)		(0.7	)		(1.2	)		(1.3	)
Total	$	(29.5	)	$	(6.7	)	$	(49.4	)	$	(13.9	)

The income tax provision for the quarters ended June 30, 2026 and June 30, 2025 was $29.5 million and $6.7 million, respectively, reflecting an effective tax rate of 23% and 22%, respectively. There was no material difference between the effective tax rate and the blended statutory tax rate for the quarters ended June 30, 2026 and 2025.

The income tax provision for the six months ended June 30, 2026 and June 30, 2025 was $49.4 million and $13.9 million, respectively, reflecting an effective tax rate of 24% and 24%, respectively. There was no material difference between the effective tax rate and the blended statutory tax rate for the six months ended June 30, 2026 and 2025.

Our gross unrecognized benefits relating to uncertain tax positions were $8.1 million and $7.4 million at June 30, 2026 and December 31, 2025, respectively. If recognized, these amounts would be reflected in our income tax provision and affect our effective tax rate.

10. Earnings Per Share

Basic net income per share is computed by dividing distributed and undistributed net income allocable to common shares by the weighted-average number of common shares outstanding during the applicable period. The basic weighted-average number of common shares outstanding during the period excludes non-vested share-based payment awards. Basic and diluted net income per share was calculated under the two-class method for the quarters and six months ended June 30, 2026 and 2025.

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NOTES TO INTERIM CONSOLIDATED FINANCIAL STATEMENTS – UNAUDITED

The following table sets forth the computation of basic and diluted net income per share (in millions of dollars, except share and per share amounts):

	Quarter Ended June 30,				Six Months Ended June 30,
	2026		2025		2026		2025
Numerator:
Net income available to common shareholders1	$	96.8	$	23.2	$	159.3	$	44.8
Denominator – Weighted-average common shares outstanding (in thousands):
Basic		16,343		16,160		16,296		16,138
Add: dilutive effect of non-vested common shares, restricted stock units and performance shares2		575		319		590		319
Diluted		16,918		16,479		16,886		16,457
Net income per common share, Basic:	$	5.92	$	1.44	$	9.77	$	2.77
Net income per common share, Diluted:	$	5.72	$	1.41	$	9.43	$	2.72

1.Represents Net income less distributed and undistributed earnings allocated to non-vested restricted stock awards that contain non-forfeitable rights to dividends.

2.Quantities in the following discussion are denoted in whole shares. During the quarter and six months ended June 30, 2026, approximately 122 and 223 shares, respectively, were excluded from the weighted-average diluted shares computation as their inclusion would have been anti‑dilutive. During the quarter and six months ended June 30, 2025, approximately 565 and 241 shares, respectively, were excluded from the weighted-average diluted shares computation as their inclusion would have been anti‑dilutive.

11. Supplemental Cash Flow Information

	Six Months Ended June 30,
	2026		2025
Interest paid	$	22.0	$	22.1
Non-cash investing and financing activities (included in Accounts payable and Other accrued liabilities):
Unpaid purchases of property and equipment	$	24.3	$	22.9
Supplemental lease disclosures:
Operating lease liabilities arising from obtaining operating lease assets	$	3.9	$	1.0
Cash paid for amounts included in the measurement of operating lease liabilities	$	3.2	$	3.6
Finance lease liabilities arising from obtaining finance lease assets	$	4.1	$	0.7

	As of June 30,
	2026		2025
Components of cash, cash equivalents and restricted cash:
Cash and cash equivalents	$	58.5	$	13.1
Restricted cash included in Other assets1		19.9		19.8
Total cash, cash equivalents and restricted cash presented on our Statements of Consolidated Cash Flows	$	78.4	$	32.9

1.We are required to keep on deposit certain amounts that are pledged or held as collateral relating to workers’ compensation and other agreements. We account for such deposits as restricted cash. From time to time, such restricted funds could be returned to us or we could be required to pledge additional cash.

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KAISER ALUMINUM CORPORATION AND SUBSIDIARY COMPANIES

NOTES TO INTERIM CONSOLIDATED FINANCIAL STATEMENTS – UNAUDITED

12. Business, Product, and Geographical Area Information

Our primary line of business is the production of semi-fabricated specialty aluminum mill products, such as plate and sheet, bare and coated coils, and extruded and drawn products, primarily used in our Aero/HS Products, Packaging, GE Products, and Automotive Extrusions end markets. We operate production facilities in the United States and Canada. We have one operating and reportable segment. Our determination that we operate as a single segment is consistent with the financial information regularly viewed by the chief operating decision maker (“CODM”) to evaluate performance and make decisions regarding resource allocation. The CODM uses Net income to measure segment profitability in deciding whether to reinvest profits into the segment or into other parts of the entity, such as for acquisitions or to pay dividends.

The following table presents the significant segment expenses that are provided to the CODM:

	Quarter Ended June 30,						Six Months Ended June 30,
	2026			2025			2026			2025
Net sales	$	1,256.6		$	823.1		$	2,363.4		$	1,600.5
Less:
Cost of products sold, excluding depreciation and amortization
Hedged cost of alloyed metal1		819.6			448.9			1,522.0			863.1
Manufacturing costs2		151.5			191.9			313.7			373.7
Plant overhead3		47.9			44.0			95.2			90.1
Freight costs		28.0			21.2			50.3			42.0
Other cost of products sold4		10.6			16.8			19.6			27.3
Depreciation and amortization		29.6			29.6			60.0			59.6
Selling, general, administrative, research and development
Research and development costs		0.7			0.3			1.3			0.6
Employee costs5		26.1			22.7			52.8			45.2
Other selling, general and administrative costs6		8.9			9.6			17.0			17.6
Restructuring costs		—			0.1			—			1.9
Interest expense		14.5			12.5			28.9			23.7
Other income, net – Note 8		(7.1	)		(4.4	)		(6.1	)		(3.0	)
Income tax provision		29.5			6.7			49.4			13.9
Net income	$	96.8		$	23.2		$	159.3		$	44.8

1.Hedged cost of alloyed metal includes cost of aluminum at the MWTP and the cost of alloying elements used in the production process. This metric is net of metal price exposure on shipments that we hedged with realized gains upon settlement of $11.4 million and $0.6 million for the quarters ended June 30, 2026 and June 30, 2025, respectively, and $18.9 million and $5.2 million for the six months ended June 30, 2026 and June 30, 2025, respectively.

2.Manufacturing costs primarily includes labor, utilities, supplies, metal valuation impacts, metal profits, and other materials, excluding alloys, incurred at our various production facilities.

3.Plant overhead includes salaried employee costs, property taxes, and insurance associated with our various production facilities.

4.Other cost of products sold primarily includes accretion expense related to conditional asset retirement obligations, gains and losses on operating asset disposals, and major maintenance costs.

5.Employee costs include indirect labor salaries, benefits, and incentive compensation.

6.Other selling, general and administrative costs primarily includes professional services, computer hardware and software costs, office rent, and utilities.

The CODM does not review asset and capital expenditure information by reportable operating segment as such information is presented to the CODM on a consolidated basis.

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KAISER ALUMINUM CORPORATION AND SUBSIDIARY COMPANIES

NOTES TO INTERIM CONSOLIDATED FINANCIAL STATEMENTS – UNAUDITED

The following table presents Net sales by end market applications and by timing of control transfer:

	Quarter Ended June 30,				Six Months Ended June 30,
	2026		2025		2026		2025
Net sales:
Aero/HS Products	$	305.3	$	227.9	$	592.1	$	442.6
Packaging		580.4		340.9		1,078.8		655.1
GE Products		280.7		185.4		521.0		367.0
Automotive Extrusions		90.2		68.9		171.5		135.8
Total net sales	$	1,256.6	$	823.1	$	2,363.4	$	1,600.5
Timing of revenue recognition:
Products transferred at a point in time	$	992.0	$	626.6	$	1,845.2	$	1,217.4
Products transferred over time		264.6		196.5		518.2		383.1
Total net sales	$	1,256.6	$	823.1	$	2,363.4	$	1,600.5

The following table presents geographic information for income taxes paid:

	Quarter Ended June 30,				Six Months Ended June 30,
	2026		2025		2026		2025
Income taxes paid:
Domestic	$	7.6	$	2.6	$	7.9	$	2.6
Foreign		0.6		0.9		1.3		2.7
Total income taxes paid	$	8.2	$	3.5	$	9.2	$	5.3

13. Subsequent Events

Dividend Declaration. On July 13, 2026, we announced that our Board of Directors declared a quarterly cash dividend of $0.77 per common share. As such, we expect to pay approximately $12.8 million (including dividend equivalents) on or about August 14, 2026 to stockholders of record and the holders of certain restricted stock units at the close of business on July 24, 2026.

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Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations

Forward-Looking Statements

This Quarterly Report on Form 10-Q contains statements which constitute “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. These statements appear throughout this Report and can be identified by the use of forward-looking terminology such as “believes,” “expects,” “may,” “estimates,” “will,” “should,” “plans” or “anticipates,” or the negative of the foregoing or other variations of comparable terminology, or by discussions of strategy. Readers are cautioned that any such forward‑looking statements are not guarantees of future performance and involve significant risks and uncertainties and that actual results may vary from those in the forward-looking statements as a result of various factors. These factors include: (i) the effectiveness of management’s strategies and decisions, including strategic investments, capital spending strategies, cost reduction initiatives, sourcing strategies, processes and countermeasures implemented to address operational and supply chain challenges and the execution of those strategies; (ii) the execution and timing of strategic investments; (iii) general economic and business conditions, including higher interest rates, the impact of geopolitical factors and governmental and other actions taken in response, tariffs, cyclicality, reshoring, sanctions and export controls, labor challenges, supply interruptions, energy price volatility, scrap availability and pricing, customer operation disruptions, including as a result of regulatory actions, customer inventory imbalances and supply chain issues, regional aluminum premium volatility, and other conditions that impact demand drivers in the Aero/HS Products, Packaging, GE Products, and Automotive Extrusions end markets we serve; (iv) our ability to participate in mature and anticipated new automotive programs expected to launch in the future and successfully launch new automotive programs, including electric vehicle platforms; (v) changes or shifts in defense spending due to competing national priorities; (vi) pricing, market conditions and our ability to effectively execute commercial and labor strategies, pass through cost increases, including the institution of surcharges, and flex costs in response to inflation, volatile commodity costs, regional aluminum premiums and energy prices, and changing economic conditions; (vii) developments in technology, including cybersecurity and artificial intelligence threats; (viii) the impact of our future earnings, cash flows, financial condition, capital requirements and other factors on our financial strength and flexibility; (ix) new or modified statutory or regulatory requirements, including evolving climate-related disclosure regimes, state-level climate programs, and packaging and recycled content laws; (x) the successful integration of acquired operations and technologies; (xi) the views of our stakeholders, including regulators and customers, regarding our sustainability goals and initiatives and the impact of factors outside of our control on such goals and initiatives, including potential greenwashing or consumer protection claims; and (xii) other factors discussed in Part I, Item 1A. “Risk Factors” of our Annual Report on Form 10-K for the year ended December 31, 2025, and in other filings we make with the SEC from time to time. No assurance can be given that these are all of the factors that could cause actual results to vary materially from the forward-looking statements. Readers are urged to consider these factors carefully in evaluating any forward-looking statements and are cautioned not to place undue reliance on such statements. We undertake no obligation to update or revise any forward-looking statements, except as required by law.

The following discussion and analysis of our financial condition and results of operations should be read in conjunction with Part I, Item 1. “Financial Statements” of this Report and our consolidated financial statements and related notes included in Part II, Item 8. “Financial Statements and Supplementary Data” of our Annual Report on Form 10-K for the year ended December 31, 2025. Unless otherwise noted, dollars in tables are presented in millions.

Business Overview

We manufacture and sell semi-fabricated specialty aluminum mill products, including flat-rolled (plate, sheet, and coil), extruded (rod, bar, hollows, and shapes), drawn (rod, bar, pipe, tube, and wire), and certain cast aluminum products. We strategically focus our business on select end markets with demanding applications and high barriers to entry, where we believe we have sustainable competitive advantages that allow us to earn premium pricing and generate long-term profitable growth. The end market applications on which we have historically focused include: (i) Aero/HS Products; (ii) Packaging; (iii) GE Products; and (iv) Automotive Extrusions. These technically challenging applications leverage our core metallurgical and process technology capabilities to produce highly engineered mill products with differentiated characteristics that are required for the particular end uses.

Within the global market for flat-rolled aluminum mill products, our focus is on two primary product categories: (i) heat treat plate, sheet and coil products and (ii) packaging coil products. Heat treat plate, sheet and coil products, which are produced at Trentwood, serve the global Aero/HS and primarily North America GE end markets and are designed for applications requiring higher strength and other specialized attributes that cannot be achieved by common alloy rolled products. Packaging coil products, which are produced at Warrick and sold primarily in North America are for demanding food and beverage can package applications. Our focus is primarily on coated packaging applications, which includes a range of colors and widths, depending on customer specifications, in addition to bare coil products.

In the areas of aluminum extrusions, we focus on demanding Aero/HS Products, GE Products, and Automotive Extrusions that require high strength, machinability, or other specialized attributes. Our 10 extrusion/drawing facilities, nine of which are in the United States and one of which is in Canada, primarily serve North American demand for aerospace, general engineering, and automotive applications. Additionally, we operate a facility in Columbia, New Jersey that focuses on multi-material advanced manufacturing

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methods and techniques, including multi-axis computer numerical control machining, additive manufacturing, welding and fabrication for demanding aerospace and defense, high technology, general industrial, and automotive applications. We employed approximately 3,800 people at June 30, 2026.

We have long-standing relationships with our customers, which consist primarily of blue-chip companies, including leading aerospace and automotive manufacturers, tier one aerospace and automotive suppliers, leading beverage and food companies, beverage and food packaging manufacturers, and metal service centers. Approximately 70% of our shipments are sold direct to manufacturers or tier one suppliers and approximately 30% are sold to metal service centers. In our served markets, we seek to be the supplier of choice by pursuing “Best in Class” customer satisfaction driven by quality, availability, service and delivery performance. We believe we differentiate our product portfolio through our broad product offering and our KaiserSelect® products, which are engineered and manufactured to deliver enhanced product characteristics with improved consistency, so as to result in better performance, lower waste and, in many cases, lower production cost for our customers.

Non-GAAP Financial Measures

This information contains certain non-GAAP financial measures. A non-GAAP financial measure is defined as a numerical measure of a company’s financial performance that excludes or includes amounts so as to be different than the most directly comparable measure calculated and presented in accordance with US GAAP in the statements of income, balance sheets, or statements of cash flows of the company. We have provided a reconciliation of non-GAAP financial measures to the most directly comparable financial measure in the accompanying tables. We have also provided a discussion of the reasons we believe that presentation of the non-GAAP financial measures provides useful information to investors, as well as any additional ways in which we use the non-GAAP financial measures. The non-GAAP financial measures used in the following discussions are Conversion Revenue (defined as Net Sales less the Hedged Cost of Alloyed Metal, see below in “Metal Pricing Policies” discussion) and Adjusted EBITDA. These measures are presented because management uses this information to monitor and evaluate financial results and trends and believes this information to also be useful for investors.

In the discussion of operating results below, we refer to certain items as “non-run-rate items.” For purposes of such discussion, non-run-rate items are items that, while they may recur from period-to-period: (i) are particularly material to results; (ii) affect costs primarily as a result of external market factors; and (iii) may not recur in future periods if the same level of underlying performance were to occur. Non-run-rate items are part of our business and operating environment but are worthy of being highlighted for the benefit of readers of our financial statements. Our intent is to allow users of the financial statements to consider our results both in light of and separately from such items. For a reconciliation of Conversion Revenue to Net sales and Adjusted EBITDA to Net income, see below in “Results of Operations - Selected Operational and Financial Information.”

Metal Pricing Policies

A fundamental aspect of our business model is to maintain relative neutrality to fluctuations in the market prices of aluminum and certain alloying elements ("metal price neutrality"). We generally achieve this objective by structuring customer pricing to pass through changes in the underlying index-based cost of aluminum and certain alloys. In instances where metal price neutrality is not fully achieved through customer pricing actions for certain alloying elements, we manage these exposures through a combination of supply arrangements, and hedging activities. Despite these pass-through mechanisms, our results of operations may be affected by timing differences between when metal costs are incurred and when those costs are reflected in customer pricing. As a result, our reported operating results may be impacted by favorable or unfavorable fluctuations in metal prices, the timing and magnitude of such fluctuations, and other market factors that could influence metal prices. Over the long term, however, our business model is designed to generate earnings primarily from the conversion of aluminum into value-added semi-fabricated products rather than from changes in underlying metal prices.

In order to allow users of our financial statements to consider the impact of aluminum and alloy cost on our Net sales, we disclose Net sales as well as Conversion Revenue, which is Net sales less the Hedged Cost of Alloyed Metal. As used in this discussion, “Hedged Cost of Alloyed Metal” is the cost of aluminum at the average MWTP plus the cost of alloying elements and any realized gains and/or losses on settled hedges related to the metal sold in the referenced period. The average MWTP of aluminum reflects the primary aluminum supply/demand dynamics in North America. For a reconciliation of Conversion Revenue to Net sales, see below in “Results of Operations - Selected Operational and Financial Information.”

Highlights for the quarter ended June 30, 2026:

• Net sales $1.26 billion; Conversion Revenue $437.0 million;

• Net income $96.8 million; Net income per diluted share $5.72; and

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• Cash dividends and dividend equivalents of $0.77 per share, or $12.8 million, paid during the quarter ended June 30, 2026.

Results of Operations

Consolidated Results of Operations

Net Sales. The following table sets forth, for the quarters ended June 30, 2026 and June 30, 2025, shipments (in millions of pounds) and Net sales by end market applications and the respective fluctuations.

	Quarter Ended June 30,
	2026				2025
	Shipments		Net sales		Shipments		Net sales		Shipment Change			% Increase (Decrease)			Net sales Change		% Increase (Decrease)
Aero/HS Products	60.8		$	305.3	59.9		$	227.9		0.9			2	%	$	77.4		34	%
Packaging	155.8			580.4	141.1			340.9		14.7			10	%		239.5		70	%
GE Products	67.7			280.7	63.4			185.4		4.3			7	%		95.3		51	%
Automotive Extrusions	21.4			90.2		24.0		68.9		(2.6	)		(11	%)		21.3		31	%
Total		305.7	$	1,256.6		288.4	$	823.1		17.3			6	%	$	433.5		53	%

The increase in Net sales primarily reflects $1.26 per pound (44%) increase in the average realized sales price and 17.3 million pound (6%) increase in shipment volume.

The following table sets forth, for the six months ended June 30, 2026 and June 30, 2025, shipments (in millions of pounds) and Net sales by end market applications and the respective fluctuations.

	Six Months Ended June 30,
	2026				2025
	Shipments		Net sales		Shipments		Net sales		Shipment Change			% Increase (Decrease)			Net sales Change		% Increase (Decrease)
Aero/HS Products	122.4		$	592.1	116.2		$	442.6		6.2			5	%	$	149.5		34	%
Packaging	302.4			1,078.8	271.3			655.1		31.1			11	%		423.7		65	%
GE Products	131.8			521.0	128.5			367.0		3.3			3	%		154.0		42	%
Automotive Extrusions	43.6			171.5		48.0		135.8		(4.4	)		(9	%)		35.7		26	%
Total		600.2	$	2,363.4		564.0	$	1,600.5		36.2			6	%	$	762.9		48	%

The increase in Net sales primarily reflects $1.10 per pound (39%) increase in the average realized sales price and 36.2 million pound (6%) increase in shipment volume.

COGS. COGS for the quarter ended June 30, 2026 totaled $1,057.6 million, or 84% of Net sales, compared to $722.8 million, or 88% of Net sales, for the quarter ended June 30, 2025. The total increase reflected the following:

	Quarter Ended June 30,
	2026		2025		Change			% Increase (Decrease)
Hedged Cost of Alloyed Metal	$	819.6	$	448.9	$	370.7			83	%
Manufacturing costs		151.5		191.9		(40.4	)		(21	%)
Plant overhead		47.9		44.0		3.9			9	%
Freight costs		28.0		21.2		6.8			32	%
Other cost of products sold		10.6		16.8		(6.2	)		(37	%)
Total	$	1,057.6	$	722.8	$	334.8			46	%

Of the $370.7 million increase in Hedged Cost of Alloyed Metal, $343.8 million was primarily due to an increase in hedged metal prices and $26.9 million was due to an increase in shipment volume (see above in our “Net Sales” discussion for further details). The $40.4 million decrease in manufacturing costs was primarily due to favorable metal consumption and valuation impacts, partially offset by higher operating costs. The $6.8 million increase in freight costs was primarily attributable to higher fuel costs, as well as higher shipment volumes. The $6.2 million decrease in other cost of products sold was primarily driven by a decrease in major maintenance costs. For a further discussion of the comparative results of operations for the quarters ended June 30, 2026 and June 30, 2025, see below in “Selected Operational and Financial Information.”

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COGS for the six months ended June 30, 2026 totaled $2,000.8 million, or 85% of Net sales, compared to $1,396.2 million, or 87% of Net sales, for the six months ended June 30, 2025. The total increase reflected the following:

	Six Months Ended June 30,
	2026		2025		Change			% Increase (Decrease)
Hedged Cost of Alloyed Metal	$	1,522.0	$	863.1	$	658.9			76	%
Manufacturing costs		313.7		373.7		(60.0	)		(16	%)
Plant overhead		95.2		90.1		5.1			6	%
Freight costs		50.3		42.0		8.3			20	%
Other cost of products sold		19.6		27.3		(7.7	)		(28	%)
Total	$	2,000.8	$	1,396.2	$	604.6			43	%

Of the $658.9 million increase in Hedged Cost of Alloyed Metal, $603.6 million was primarily due to an increase in hedged metal prices and $55.3 million was due to an increase in shipment volume (see above in our “Net Sales” discussion for further details). The $60.0 million decrease in manufacturing costs was primarily due to favorable metal consumption and valuation impacts, partially offset by higher operating costs. The $8.3 million increase in freight costs was primarily attributable to higher fuel costs, as well as higher shipment volumes. The $7.7 million decrease in other cost of products sold was primarily driven by a decrease in major maintenance costs. For a further discussion of the comparative results of operations for the six months ended June 30, 2026 and June 30, 2025, see below in “Selected Operational and Financial Information.”

Selling, General, Administrative, Research and Development (“SG&A and R&D”). SG&A and R&D expense totaled $35.7 million and $32.6 million for the quarters ended June 30, 2026 and June 30, 2025, respectively. The increase in employee costs was primarily driven by higher incentive costs. The total increase in SG&A and R&D reflected the following:

	Quarter Ended June 30,
	2026		2025		Change			% Increase (Decrease)
Research and development costs	$	0.7	$	0.3	$	0.4			133	%
Employee costs		26.1		22.7		3.4			15	%
Other selling, general and administrative costs		8.9		9.6		(0.7	)		(7	%)
Total	$	35.7	$	32.6	$	3.1			10	%

SG&A and R&D expense totaled $71.1 million and $63.4 million for the six months ended June 30, 2026 and June 30, 2025, respectively. The increase in employee costs was primarily driven by higher incentive costs. The total increase in SG&A and R&D reflected the following:

	Six Months Ended June 30,
	2026		2025		Change			% Increase (Decrease)
Research and development costs	$	1.3	$	0.6	$	0.7			117	%
Employee costs		52.8		45.2		7.6			17	%
Other selling, general and administrative costs		17.0		17.6		(0.6	)		(3	%)
Total	$	71.1	$	63.4	$	7.7			12	%

Restructuring Costs. During the quarter ended March 31, 2025, we initiated a plan to reduce certain operating costs (the “2025 Restructuring Plan”). In the quarter and six months ended June 30, 2025, restructuring costs of $0.1 million and $6.8 million, respectively, represented severance and related benefits under the plan. Substantially all costs associated with the 2025 Restructuring Plan were incurred and expensed as of December 31, 2025, and no restructuring costs were incurred during the quarter or six months ended June 30, 2026.

Interest Expense. See Note 5 of Notes to Interim Consolidated Financial Statements included in this Report for a discussion of our debt and credit facilities that were in effect during the quarters and six months ended June 30, 2026 and June 30, 2025 and interest expense capitalized as part of construction in progress.

Other Income, Net. See Note 8 of Notes to Interim Consolidated Financial Statements included in this Report for details.

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Income Tax Provision. See Note 9 of Notes to Interim Consolidated Financial Statements included in this Report for disclosure regarding our income tax provision.

Selected Operational and Financial Information

The following data should be read in conjunction with our consolidated financial statements and the notes thereto included in Part I, Item 1. “Financial Statements” of this Report. Interim results are not necessarily indicative of those for a full year.

The table below provides selected operational and financial information:

	Quarter Ended June 30,						Six Months Ended June 30,
	2026			2025			2026			2025
Net income	$	96.8		$	23.2		$	159.3		$	44.8
Interest expense		14.5			12.5			28.9			23.7
Other income, net		(7.1	)		(4.4	)		(6.1	)		(3.0	)
Income tax provision		29.5			6.7			49.4			13.9
Depreciation and amortization		29.6			29.6			60.0			59.6
Non-run-rate items:
Restructuring costs		—			0.1			—			1.9
Environmental expenses1		0.1			—			0.1			0.2
Loss on disposition of operating property, plant and equipment		2.9			—			3.2			—
Total non-run-rate items		3.0			0.1			3.3			2.1
Adjusted EBITDA2	$	166.3		$	67.7		$	294.8		$	141.1

1.Non-run-rate environmental expenses are related to legacy contingencies from activities at operating facilities prior to July 6, 2006. See Note 6 of Notes to Interim Consolidated Financial Statements included in this Report for additional information relating to the environmental expenses.

2.Adjusted EBITDA includes favorable Metal Price Lag of approximately $27.0 million and approximately $14.0 million for the quarters ended June 30, 2026 and June 30, 2025, respectively, and favorable Metal Price Lag of approximately $64.0 million and approximately $36.0 million for the six months ended June 30, 2026 and June 30, 2025, respectively.

Adjusted EBITDA for the quarter ended June 30, 2026 was $98.6 million higher than Adjusted EBITDA for the quarter ended June 30, 2025. Adjusted EBITDA for the quarter ended June 30, 2026 was favorably impacted by: (i) higher sales volume; (ii) improved product pricing and mix; (iii) favorable metal consumption and valuation impacts; and (iv) lower major maintenance costs. This was partially offset by: (i) higher operating costs and (ii) higher employee and employee-related costs. See above in “Consolidated Results of Operations” for further details.

Adjusted EBITDA for the six months ended June 30, 2026 was $153.7 million higher than Adjusted EBITDA for the six months ended June 30, 2025. Adjusted EBITDA for the six months ended June 30, 2026 was favorably impacted by: (i) higher sales volume; (ii) improved product pricing and mix; (iii) favorable metal consumption and valuation impacts; and (iv) lower major maintenance costs. This was partially offset by: (i) higher operating costs and (ii) higher employee and employee-related costs. See above in “Consolidated Results of Operations” for further details.

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The following table provides our shipment and Conversion Revenue information (in millions of dollars, except shipments and Conversion Revenue per pound) by end market applications:

	Quarter Ended June 30,												Six Months Ended June 30,
	2026						2025						2026						2025
Aero/HS Products:
Shipments (mmlbs)	60.8						59.9						122.4						116.2
	$			$ / lb			$			$ / lb			$			$ / lb			$			$ / lb
Net sales	$	305.3		$	5.02		$	227.9		$	3.80		$	592.1		$	4.84		$	442.6		$	3.81
Less: Hedged Cost of Alloyed Metal		(169.5	)		(2.79	)		(100.7	)		(1.68	)		(325.8	)		(2.66	)		(194.9	)		(1.68	)
Conversion Revenue	$	135.8		$	2.23		$	127.2		$	2.12		$	266.3		$	2.18		$	247.7		$	2.13
Packaging:
Shipments (mmlbs)	155.8						141.1						302.4						271.3
	$			$ / lb			$			$ / lb			$			$ / lb			$			$ / lb
Net sales	$	580.4		$	3.73		$	340.9		$	2.42		$	1,078.8		$	3.57		$	655.1		$	2.41
Less: Hedged Cost of Alloyed Metal		(406.4	)		(2.61	)		(211.2	)		(1.50	)		(747.4	)		(2.47	)		(398.0	)		(1.46	)
Conversion Revenue	$	174.0		$	1.12		$	129.7		$	0.92		$	331.4		$	1.10		$	257.1		$	0.95
GE Products:
Shipments (mmlbs)	67.7						63.4						131.8						128.5
	$			$ / lb			$			$ / lb			$			$ / lb			$			$ / lb
Net sales	$	280.7		$	4.15		$	185.4		$	2.92		$	521.0		$	3.95		$	367.0		$	2.86
Less: Hedged Cost of Alloyed Metal		(185.1	)		(2.74	)		(99.7	)		(1.57	)		(338.0	)		(2.56	)		(197.8	)		(1.54	)
Conversion Revenue	$	95.6		$	1.41		$	85.7		$	1.35		$	183.0		$	1.39		$	169.2		$	1.32
Automotive Extrusions:
Shipments (mmlbs)	21.4						24.0						43.6						48.0
	$			$ / lb			$			$ / lb			$			$ / lb			$			$ / lb
Net sales	$	90.2		$	4.21		$	68.9		$	2.87		$	171.5		$	3.93		$	135.8		$	2.83
Less: Hedged Cost of Alloyed Metal		(58.6	)		(2.73	)		(37.3	)		(1.55	)		(110.8	)		(2.54	)		(72.4	)		(1.51	)
Conversion Revenue	$	31.6		$	1.48		$	31.6		$	1.32		$	60.7		$	1.39		$	63.4		$	1.32
Total:
Shipments (mmlbs)	305.7						288.4						600.2						564.0
	$			$ / lb			$			$ / lb			$			$ / lb			$			$ / lb
Net sales	$	1,256.6		$	4.11		$	823.1		$	2.85		$	2,363.4		$	3.94		$	1,600.5		$	2.84
Less: Hedged Cost of Alloyed Metal1		(819.6	)		(2.68	)		(448.9	)		(1.55	)		(1,522.0	)		(2.54	)		(863.1	)		(1.53	)
Conversion Revenue	$	437.0		$	1.43		$	374.2		$	1.30		$	841.4		$	1.40		$	737.4		$	1.31

1.The total Hedged Cost of Alloyed Metal includes cost of aluminum at the MWTP and the cost of alloying elements used in the production process. This metric is net of metal price exposure on shipments that we hedged with realized gains upon settlement of $11.4 million and $0.6 million for the quarters ended June 30, 2026 and June 30, 2025, respectively, and $18.9 million and $5.2 million for the six months ended June 30, 2026 and June 30, 2025, respectively. See Note 4 of Notes to Interim Consolidated Financial Statements included in this Report for the total realized gains and losses on aluminum hedges for which we hedged the metal price exposure externally.

Outlook

We continue to believe we are well positioned going into the second half of 2026. Demand continues to strengthen across most of our key end markets, customer activity remains robust, and bookings now extend well into next year in several areas of the business. From an end market perspective, Aero/HS Products continues to recover and grow, Packaging is delivering the benefits of our transformation at Warrick, GE Products is increasingly benefiting from solid, structural demand drivers along with restocking at service centers, and Automotive Extrusions demand along with our planned investments will provide future growth in our targeted applications.

27

Our outlook for the rest of the year assumes:

•neutral metal price impact through the end of the year without a continuation of metal tailwinds recorded to date;

•continued focus on improving operational efficiencies; and

•leveraging recent capital investments to support continued margin expansion.

Accordingly, we expect a 10% to 15% year-over-year improvement in Conversion Revenue and a 45% to 55% year-over-year growth in Adjusted EBITDA for the full year 2026.

Liquidity and Capital Resources

Summary

The following table summarizes our liquidity:

	As of June 30, 2026		As of December 31, 2025
Available cash and cash equivalents	$	58.5	$	7.0
Borrowing availability under Revolving Credit Facility, net of letters of credit1		569.9		540.2
Total liquidity	$	628.4	$	547.2

1.Borrowing availability under the Revolving Credit Facility was determined by a borrowing base calculated as of June 30, 2026 and December 31, 2025.

We place our cash in bank deposits with high credit quality financial institutions. See Note 11 of Notes to Interim Consolidated Financial Statements included in this Report for information regarding restricted cash at June 30, 2026.

We had no outstanding borrowings under the Revolving Credit Facility as of June 30, 2026. During the six months ended June 30, 2026, we repaid $420.1 million of borrowings, consisting of the full repayment of the $22.3 million outstanding balance as of December 31, 2025 and $397.8 million of borrowings incurred during the six months ended June 30, 2026. See below in “Sources of Liquidity” for a further discussion of subsequent borrowing activity. See Note 5 of Notes to Interim Consolidated Financial Statements included in this Report.

Cash Flows

The following table summarizes our cash flows from operating, investing, and financing activities:

	Six Months Ended June 30,
	2026			2025
Total cash provided by (used in):
Operating activities	$	147.4		$	72.9
Investing activities	$	(36.7	)	$	(81.9	)
Financing activities	$	(59.2	)	$	4.0

Cash provided by operating activities for the six months ended June 30, 2026 reflected results of business activity described above in our “Consolidated Results of Operations” discussion, as well as the following working capital changes: (i) an increase in accounts payable of $229.0 million, primarily due to timing of payments and higher metal costs; (ii) an increase in receivables of $151.8 million, primarily due to increased metal prices and higher shipment volume; (iii) an increase in inventory of $123.6 million, due to higher metal costs; and (iv) a decrease in accrued liabilities of $48.8 million, primarily due to timing.

Cash provided by operating activities for the six months ended June 30, 2025 reflected results of business activity described above in our “Consolidated Results of Operations” discussion, as well as the following working capital changes: (i) an increase in receivables of $75.9 million, primarily due to increased metal prices; (ii) a decrease in accrued liabilities of $26.0 million, primarily due to timing of uncleared cash disbursements; (iii) an increase in accounts payable of $45.7 million, primarily due to the timing of payments and higher metal cost; and (iv) a decrease in inventory of $6.3 million, primarily due to a reduction in total inventory pounds in connection with our continued focus on inventory management, offset by increased metal prices.

See Statements of Consolidated Cash Flows included in this Report for further details on our cash flows from operating, investing, and financing activities for the six months ended June 30, 2026 and 2025.

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Sources of Liquidity

Our most significant sources of liquidity include available cash and cash equivalents, available credit under the Revolving Credit Facility, and funds generated from operations. We believe we have sufficient liquidity to fund our operations and meet our short-term and long-term obligations.

Our Revolving Credit Facility and outstanding Senior Notes have covenants that, we believe, allow us to operate our business with limited restrictions and significant flexibility for the foreseeable future. We believe the covenants contained in the Revolving Credit Facility will not limit our ability to raise additional debt or equity to satisfy our foreseeable liquidity needs during the next 12 months, should we choose to do so. We also do not believe it is likely that, during the next 12 months, we will trigger the availability threshold that would require measuring and maintaining a fixed charge coverage ratio.

At July 20, 2026, we had no outstanding borrowings under the Revolving Credit Facility. See Note 9 of Notes to Consolidated Financial Statements included in our Annual Report on Form 10-K for the year ended December 31, 2025 for a description of our Revolving Credit Facility.

We engage in certain customer-based supply chain financing programs to accelerate the receipt of payment for outstanding accounts receivable from certain customers. Costs of these programs are typically reimbursed to us by the customer. Receivables transferred under these customer-based supply chain financing programs generally meet the requirements to be accounted for as sales resulting in the derecognition of such receivables from our consolidated balance sheets. Receivables involved with these customer‑based supply chain finance programs for the quarter ended June 30, 2026 constituted approximately 27% of our Net sales. See Note 8 of Notes to Interim Consolidated Financial Statements included in this Report for further details with respect to these supply chain financing programs.

Material Cash Requirements

See Note 9 of Notes to Consolidated Financial Statements included in Part II, Item 8. “Financial Statements and Supplementary Data” in our Annual Report on Form 10-K for the year ended December 31, 2025 for mandatory principal and cash interest payments on the outstanding borrowings. We do not believe that covenants in the indentures governing the Senior Notes are reasonably likely to limit our ability to obtain additional debt or equity financing should we choose to do so during the next 12 months. Except as otherwise disclosed in this Report, there has been no material change in our material cash requirements from significant contractual obligations, commercial commitments, or off-balance sheet arrangements other than in the ordinary course of business since December 31, 2025.

Capital Expenditures and Investments

We strive to strengthen our competitive position across our end markets through strategic capital investment aimed at increasing our capacity and expanding our manufacturing capabilities. While some of our recent capital projects have focused on further enhancing manufacturing cost efficiency, improving product quality, and promoting operational security, a significant portion over the past several years related to our investment in a fourth coating line at Warrick to increase our capacity for higher margin coated aluminum material for packaging applications and the Trentwood modernization projects, which focused on equipment upgrades throughout the process flow to reduce conversion costs, increase efficiency and process flow for heat-treated plate to achieve KaiserSelect® quality enhancements for Aero/HS Products and GE Products, and further improve our competitive cost position on all products produced at Trentwood. These improvements have allowed us to gain incremental manufacturing capacity and product performance to enable future sales growth.

Our capital investment plans remain focused on supporting demand growth through capacity expansion, sustaining our operations, enhancing product quality and increasing operating efficiencies. We anticipate total capital spending in 2026 of approximately $120.0 million to $130.0 million. We expect to continue to deploy capital thoughtfully so that investment decisions align with demand expectations in order to maximize the earnings potential of the business and maintain financial strength and flexibility.

Capital investments will be funded using cash generated from operations, available cash and cash equivalents, borrowings under the Revolving Credit Facility and/or other third-party financing arrangements. The level of anticipated capital expenditures may be adjusted from time to time depending on our business plans, our price outlook for fabricated aluminum products, our ability to maintain adequate liquidity, and other factors. No assurance can be provided as to the timing of any such expenditures or the operational benefits expected therefrom.

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Dividends

We have consistently paid a quarterly cash dividend since the second quarter of 2007 to holders of our common stock, including holders of restricted stock. Nevertheless, as in the past, the future declaration and payment of dividends, if any, will be at the discretion of our Board of Directors and will depend on a number of factors, including our financial and operating results, including the availability of surplus and/or net profits, liquidity position, anticipated cash requirements and contractual restrictions under our Revolving Credit Facility, the indentures for our Senior Notes or other indebtedness we may incur in the future. We can give no assurance that dividends will be declared and paid in the future.

We also pay quarterly dividend equivalents to the holders of certain restricted stock units. Holders of performance shares are not paid a quarterly dividend equivalent, but instead are entitled to receive, in connection with the issuance of underlying shares of common stock for performance shares that ultimately vest, a one-time payment equal to the dividends such holders would have received if the number of such shares of common stock so issued had been held of record by such holders from the date of grant of such performance shares through the date of such issuance.

See our Statements of Consolidated Stockholders’ Equity and Note 13 of Notes to Interim Consolidated Financial Statements included in this Report for information regarding dividends paid during the quarters ended June 30, 2026 and June 30, 2025, and declared subsequent to June 30, 2026.

Repurchases of Common Stock

We have not completed any share repurchases since March 2020. We will continue to assess share repurchases as a part of our capital allocation priorities and strategic investment opportunities identified to support further growth in our business. At June 30, 2026, $93.1 million remained authorized and available for future repurchases of common stock under our stock repurchase program.

See our Statements of Consolidated Stockholders’ Equity included in this Report for information regarding minimum statutory tax withholding obligations arising during the quarters ended June 30, 2026 and June 30, 2025 in connection with the vesting of non‑vested shares, restricted stock units, and performance shares.

Critical Accounting Estimates and Policies

Our consolidated financial statements are prepared in accordance with GAAP. In connection with the preparation of our financial statements, we are required to make assumptions and estimates about future events and apply judgments that affect the reported amounts of assets, liabilities, revenue and expenses and the related disclosures. We base our assumptions, estimates and judgments on historical experience, current trends and other factors that management believes to be relevant at the time our consolidated financial statements are prepared. On a regular basis, management reviews the accounting policies, assumptions, estimates and judgments to ensure that our financial statements are presented fairly and in accordance with GAAP. However, because future events and their effects cannot be determined with certainty, actual results could differ from our assumptions and estimates and such differences could be material.

Our significant accounting policies are discussed in Note 1 of Notes to Consolidated Financial Statements included in our Annual Report on Form 10-K for the year ended December 31, 2025. We discuss our critical accounting estimates in Part II, Item 7. “Management’s Discussion and Analysis of Financial Condition and Results of Operations” of our Annual Report on Form 10‑K for the year ended December 31, 2025. There have been no material changes in our critical accounting estimates and policies since December 31, 2025.

New Accounting Pronouncements

Information regarding new accounting pronouncements is included in Note 1 of our Interim Consolidated Financial Statements in this Form 10-Q.

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Availability of Information

We file Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K, Proxy Statements, any amendments to those reports and statements and other information with the SEC. You may obtain the documents that we file electronically from the SEC’s website at http://www.sec.gov. Our filings with the SEC are made available free of charge on our website at http://www.kaiseraluminum.com as soon as reasonably practicable after we file or furnish the materials with the SEC. News releases, announcements of upcoming earnings calls and events in which our management participates or hosts with members of the investment community and an archive of webcasts of such earnings calls and investor events and related investor presentations, are also available on our website. Information on our website is not incorporated into this Form 10-Q unless expressly noted.

Item 3. Quantitative and Qualitative Disclosures About Market Risk

The following quantitative and qualitative disclosures about market risk should be read in conjunction with Note 4 and Note 7 of Notes to Interim Consolidated Financial Statements included in this Report. Our operating results are sensitive to changes in the prices of primary aluminum, certain alloying metals, natural gas, electricity, and foreign currency, and also depend to a significant degree upon the volume and mix of products sold to customers. We have historically utilized hedging transactions to lock in a specified price or range of prices for certain products which we sell or consume in our production process, and to mitigate our exposure to changes in energy prices.

Aluminum

During the six months ended June 30, 2026 and 2025, settlements of derivative contracts were for 111.4 million pounds and 61.5 million pounds, respectively, of hedged shipments sold on pricing terms that created aluminum price risk for us. At June 30, 2026, we had derivative contracts with respect to approximately 70.1 million pounds and 6.1 million pounds to hedge sales to be made during the remainder of 2026 and 2027, respectively, on pricing terms that create aluminum price risk for us.

Based on the aluminum derivative positions held by us to hedge firm-price customer sales agreements, we estimate that a $0.10/lb decrease in the LME market price of aluminum as of June 30, 2026 and December 31, 2025, with all other variables held constant, would have resulted in an unrealized mark-to-market loss of $7.6 million and $2.5 million, respectively, with corresponding changes to the net fair value of our aluminum derivative positions. Additionally, we estimate that a $0.05/lb decrease in the MWP as of June 30, 2026 and December 31, 2025, with all other variables held constant, would have resulted in an unrealized mark-to-market loss of $3.8 million and $0.8 million, respectively, with corresponding changes to the net fair value of our aluminum derivative positions.

Alloying Metals

We are exposed to the risk of fluctuating prices of certain alloying metals, especially copper, zinc, and magnesium, to the extent that changes in their prices do not highly correlate with price changes for aluminum. Copper, zinc, magnesium, and certain other metals are used in our remelt operations to cast rolling ingot and extrusion billet with the proper chemistry for our products. From time to time, we enter into forward contract swaps and/or physical delivery commitments with third parties to mitigate our risk from fluctuations in the prices of these alloys. As of June 30, 2026, we had forward swap contracts with settlement dates designed to align with the timing of scheduled purchases of zinc and copper by our manufacturing facilities. We estimate that a $0.10/lb decrease in the market price of zinc and copper as of June 30, 2026 and December 31, 2025, with all other variables held constant, would have resulted in an unrealized mark‑to‑market loss of $0.5 million and $0.6 million, respectively, with corresponding changes to the net fair value of our zinc and copper derivative positions.

Energy

We are exposed to the risk of fluctuating prices for natural gas and electricity. We, from time to time, in the ordinary course of business, enter into hedging transactions and/or firm-price physical delivery commitments with third parties to mitigate our risk from fluctuations in natural gas and electricity prices. We estimate that a $1.00 per mmbtu decrease in natural gas prices would have resulted in an unrealized mark-to-market loss of $4.3 million and $3.1 million as of June 30, 2026 and December 31, 2025, respectively, with corresponding changes to the net fair value of our natural gas derivative positions. We estimate that a $5.00 per Mwh decrease in electricity prices would have resulted in an unrealized mark-to-market loss of $1.9 million, as of June 30, 2026, with corresponding changes to the net fair value of our electricity derivative positions. We had no outstanding electricity derivative positions as of December 31, 2025.

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Foreign Currency

As of June 30, 2026, we maintained limited foreign currency hedge positions related to certain Euro-denominated operating and capital expenditures using forward swap contracts with settlement dates through July 2027. Due to the limited amount of outstanding foreign currency derivative positions, a hypothetical change in foreign currency exchange rates would not have had a material effect on the fair value of our foreign currency derivative positions as of June 30, 2026.

Item 4. Controls and Procedures

Evaluation of Disclosure Controls and Procedures. We maintain disclosure controls and procedures that are designed to ensure that information required to be disclosed in our reports under the Securities Exchange Act of 1934 is processed, recorded, summarized and reported within the time periods specified in the SEC’s rules and forms and that such information is accumulated and communicated to management, including the principal executive officer and principal financial officer, to allow for timely decisions regarding required disclosure. In designing and evaluating the disclosure controls and procedures, management recognizes that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving the desired control objectives, and management is required to apply its judgment in evaluating the cost-benefit relationship of possible controls and procedures. An evaluation of the effectiveness of the design and operation of our disclosure controls and procedures was performed as of the end of the period covered by this Report under the supervision of and with the participation of our management, including the principal executive officer and principal financial officer. Based on that evaluation, our principal executive officer and principal financial officer concluded that our disclosure controls and procedures were effective as of June 30, 2026 at the reasonable assurance level.

Changes in Internal Control Over Financial Reporting. We had no changes in our internal control over financial reporting during the six months ended June 30, 2026 that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

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PART II – OTHER INFORMATION

Item 1. Legal Proceedings

Reference is made to Part I, Item 3. “Legal Proceedings” included in our Annual Report on Form 10-K for the year ended December 31, 2025 for information concerning material legal proceedings with respect to the Company. There have been no material developments since December 31, 2025.

Item 1A. Risk Factors

Reference is made to Part I, Item 1A. “Risk Factors” included in our Annual Report on Form 10-K for the year ended December 31, 2025 for information concerning risk factors. There have been no material changes in risk factors since December 31, 2025.

Item 2. Unregistered Sales of Equity Securities and Use of Proceeds

The following table provides information regarding our repurchases of our common shares during the quarter ended June 30, 2026:

	Equity Incentive Plan				Stock Repurchase Plan
	Total Number of Shares Purchased1		Average Price per Share		Total Number of Shares Purchased2		Average Price per Share		Maximum Dollar Value of Shares that May Yet Be Purchased Under the Programs (millions)2
April 1, 2026 - April 30, 2026		160	$	131.62		—	$	—	$	93.1
May 1, 2026 - May 31, 2026		—		—		—		—		93.1
June 1, 2026 - June 30, 2026		102		178.16		—		—		93.1
Total		262	$	149.74		—	$	—	n/a

1.Under our equity incentive plan, participants may elect to have us withhold common shares to satisfy minimum statutory tax withholding obligations arising from the recognition of income and the vesting of restricted stock, restricted stock units, and performance shares. When we withhold these shares, we are required to remit to the appropriate taxing authorities the market price of the shares withheld by us on the date of withholding. The withholding of common shares by us could be deemed a purchase of such common shares.

2.In September 2018, our Board of Directors authorized us to repurchase an indeterminate number of shares of our common stock at an aggregate market value of up to $100.0 million. At June 30, 2026, $93.1 million remained available to repurchase our common shares pursuant to the stock repurchase program. The September 2018 authorization does not have an expiration date.

Item 3. Defaults Upon Senior Securities

None.

Item 4. Mine Safety Disclosures

Not applicable.

Item 5. Other Information

Rule 10b5-1 Trading Arrangements. During the quarter ended June 30, 2026, no director or officer of the Company adopted, modified, or terminated a "Rule 10b5-1 trading arrangement" or "non-Rule 10b5-1 trading arrangement" as each term is defined in Item 408 of Regulation S-K.

33

*Item 6. Exhibits

Exhibit		Provided	Incorporated by Reference
No.	Exhibit Description	Herewith	Form	File Number	Exhibit	Filing Date
10.1	Kaiser Aluminum Corporation 2021 Equity and Incentive Compensation Plan (Amended and Restated Effective June 4, 2026).		8-K	001-09447	10.1	June 4, 2026
31.1	Certification of Keith A. Harvey pursuant to Section 302 of the Sarbanes-Oxley Act of 2002	X
31.2	Certification of Neal E. West pursuant to Section 302 of the Sarbanes-Oxley Act of 2002	X
32.1	Certification of Keith A. Harvey pursuant to Section 906 of the Sarbanes-Oxley Act of 2002	X
32.2	Certification of Neal E. West pursuant to Section 906 of the Sarbanes-Oxley Act of 2002	X
101.INS	Inline XBRL Instance Document – the instance document does not appear in the Interactive Data File because its XBRL tags are embedded within the Inline XBRL document
101.SCH	Inline XBRL Taxonomy Extension Schema	X
104	Cover Page Interactive Data File (formatted as Inline XBRL and contained in Exhibit 101)	X

34

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this Report to be signed on its behalf by the undersigned thereunto duly authorized.

KAISER ALUMINUM CORPORATION

/s/ Neal E. West

Neal E. West

Executive Vice President and Chief Financial Officer

(Principal Financial Officer)

/s/ Vijai Narayan

Vijai Narayan

Vice President and Chief Accounting Officer

(Principal Accounting Officer)

Date: July 23, 2026

35

EX-31.1

Exhibit 31.1

CERTIFICATION PURSUANT TO SECTION 302

OF THE SARBANES-OXLEY ACT OF 2002

I, Keith A. Harvey, certify that:

1.I have reviewed this report on Form 10-Q of Kaiser Aluminum Corporation;

2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3.Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4.The registrant’s other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

(a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

(b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c)Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

(d)Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5.The registrant’s other certifying officer(s) and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

(a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

(b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

		/s/ Keith A. Harvey
		Keith A. Harvey
		President and Chief Executive Officer
Date:	July 23, 2026	(Principal Executive Officer)

EX-31.2

Exhibit 31.2

CERTIFICATION PURSUANT TO SECTION 302

OF THE SARBANES-OXLEY ACT OF 2002

I, Neal E. West, certify that:

1.I have reviewed this report on Form 10-Q of Kaiser Aluminum Corporation;

2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3.Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4.The registrant’s other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

(a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

(b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c)Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

(d)Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5.The registrant’s other certifying officer(s) and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

(a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

(b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

		/s/ Neal E. West
		Neal E. West
		Executive Vice President and Chief Financial Officer
Date:	July 23, 2026	(Principal Financial Officer)

EX-32.1

Exhibit 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. 1350

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

July 23, 2026

In connection with the Quarterly Report on Form 10-Q by Kaiser Aluminum Corporation, a Delaware corporation (the “Company”), for the quarter ended June 30, 2026 (the “Report”), as filed on the date hereof with the Securities and Exchange Commission, the undersigned, Keith A. Harvey, President and Chief Executive Officer of the Company, does hereby certify, pursuant to 18 U.S.C. 1350 as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that to such officer’s knowledge:

(1)The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 (15 U.S.C. 78m or 78o(d)); and

(2)The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company as of the dates and for the periods expressed in the Report.

IN WITNESS WHEREOF, the undersigned has executed this certification as of the date first above written.

/s/ Keith A. Harvey

Keith A. Harvey

President and Chief Executive Officer

(Principal Executive Officer)

EX-32.2

Exhibit 32.2

CERTIFICATION PURSUANT TO

18 U.S.C. 1350

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

July 23, 2026

In connection with the Quarterly Report on Form 10-Q by Kaiser Aluminum Corporation, a Delaware corporation (the “Company”), for the quarter ended June 30, 2026 (the “Report”), as filed on the date hereof with the Securities and Exchange Commission, the undersigned, Neal E. West, Executive Vice President and Chief Financial Officer of the Company, does hereby certify, pursuant to 18 U.S.C. 1350 as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that to such officer’s knowledge:

(1)The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 (15 U.S.C. 78m or 78o(d)); and

(2)The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company as of the dates and for the periods expressed in the Report.

IN WITNESS WHEREOF, the undersigned has executed this certification as of the date first above written.

/s/ Neal E. West

Neal E. West

Executive Vice President and Chief Financial Officer

(Principal Financial Officer)

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Document Period End Date	Jun. 30, 2026
Document Transition Report	false
Entity File Number	1-09447
Entity Registrant Name	KAISER ALUMINUM CORPORATION
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	94-3030279
Entity Address, Address Line One	1550 West McEwen Drive
Entity Address, Address Line Two	Suite 500
Entity Address, City or Town	Franklin
Entity Address, State or Province	TN
Entity Address, Postal Zip Code	37067
City Area Code	629
Local Phone Number	252-7040
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Title of 12(b) Security	Common stock, par value $0.01 per share
Trading Symbol	KALU
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding		16,349,092
Entity Central Index Key	0000811596
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2026
Document Fiscal Period Focus	Q2
Amendment Flag	false

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CONSOLIDATED BALANCE SHEETS (UNAUDITED) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Current assets:
Cash and cash equivalents	$ 58.5	$ 7.0
Receivables, net	575.0	423.3
Contract assets	72.3	63.4
Inventories	848.1	725.2
Prepaid expenses and other current assets	47.9	42.6
Total current assets	1,601.8	1,261.5
Property, plant and equipment, net	1,143.7	1,145.2
Operating lease assets	23.3	22.4
Deferred tax assets, net	0.0	0.2
Intangible assets, net	38.7	41.0
Goodwill	18.8	18.8
Other assets	83.3	75.7
Total assets	2,909.6	2,564.8
Current liabilities:
Accounts payable	507.2	274.6
Accrued salaries, wages and related expenses	53.6	61.3
Other accrued liabilities	81.1	91.3
Total current liabilities	641.9	427.2
Long-term portion of operating lease liabilities	21.4	21.7
Pension and OPEB	72.3	73.4
Deferred tax liabilities	106.6	75.4
Long-term liabilities	85.3	81.4
Long-term debt, net	1,038.3	1,059.6
Total liabilities	1,965.8	1,738.7
Commitments and contingencies - Note 6
Stockholders’ equity:
Preferred stock, 5,000,000 shares authorized at both June 30, 2026 and December 31, 2025; no shares were issued and outstanding at June 30, 2026 and December 31, 2025	0.0	0.0
Common stock, par value $0.01, 90,000,000 shares authorized at both June 30, 2026 and December 31, 2025; 23,184,378 shares issued and 16,349,092 shares outstanding at June 30, 2026; 23,045,729 shares issued and 16,210,443 shares outstanding at December 31, 2025	0.2	0.2
Additional paid in capital	1,134.4	1,132.5
Retained earnings	275.4	142.5
Treasury stock, at cost, 6,835,286 shares at both June 30, 2026 and December 31, 2025	(475.9)	(475.9)
AOCI	9.7	26.8
Total stockholders’ equity	943.8	826.1
Total liabilities and stockholders' equity	$ 2,909.6	$ 2,564.8

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CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) - $ / shares	Jun. 30, 2026	Dec. 31, 2025
Statement of Financial Position [Abstract]
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	90,000,000	90,000,000
Common Stock, shares issued	23,184,378	23,045,729
Common stock, shares outstanding	16,349,092	16,210,443
Treasury stock, shares	6,835,286	6,835,286

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STATEMENTS OF CONSOLIDATED INCOME (UNAUDITED) - USD ($) shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026		Jun. 30, 2025
Income Statement [Abstract]
Net sales	$ 1,256.6	$ 823.1	$ 2,363.4		$ 1,600.5
Costs and expenses:
Cost of products sold, excluding depreciation and amortization	1,057.6	722.8	2,000.8		1,396.2
Depreciation and amortization	29.6	29.6	60.0		59.6
Selling, general, administrative, research and development	35.7	32.6	71.1		63.4
Restructuring costs	0.0	0.1	0.0		1.9
Total costs and expenses	1,122.9	785.1	2,131.9		1,521.1
Operating income	133.7	38.0	231.5		79.4
Other (expense) income:
Interest expense	(14.5)	(12.5)	(28.9)		(23.7)
Other income, net - Note 8	7.1	4.4	6.1		3.0
Income before income taxes	126.3	29.9	208.7		58.7
Income tax provision	(29.5)	(6.7)	(49.4)		(13.9)
Net income	$ 96.8	$ 23.2	$ 159.3	[1]	$ 44.8	[1]
Net income per common share:
Basic	$ 5.92	$ 1.44	$ 9.77		$ 2.77
Diluted	$ 5.72	$ 1.41	$ 9.43		$ 2.72
Weighted-average number of common shares outstanding (in thousands):
Basic	16,343	16,160	16,296		16,138
Diluted	16,918	16,479	16,886		16,457

[1] See Note 11 for supplemental cash flow information.