KAISER ALUMINUM CORP

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

(Rule 14a-101)

INFORMATION REQUIRED IN PROXY STATEMENT

SCHEDULE 14A INFORMATION

PROXY STATEMENT PURSUANT TO SECTION 14(a) OF

THE SECURITIES EXCHANGE ACT OF 1934 (AMENDMENT NO. )

Filed by the Registrant ☑

Filed by a Party other than the Registrant ☐

Check the appropriate box:

☐ Preliminary Proxy Statement

☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

☑ Definitive Proxy Statement

☐ Definitive Additional Materials

☐ Soliciting Material Pursuant to §240.14a-12

(Name of Registrant as Specified in Its Charter)

(Name of Person(s) Filing Proxy Statement, if Other Than the Registrant)

Payment of Filing Fee (Check all boxes that apply):

☑ No fee required

☐ Fee paid previously with preliminary materials

☐ Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a-6(i)(1) and 0-11

LETTER TO OUR STOCKHOLDERS

FROM OUR CHAIRMAN OF THE BOARD, PRESIDENT AND CHIEF EXECUTIVE OFFICER

AND OUR LEAD INDEPENDENT DIRECTOR

April 28, 2025

Dear Stockholder:

On behalf of our Board of Directors and management team, we thank you for your continued support of Kaiser Aluminum Corporation. It is our pleasure to invite you to attend the Annual Meeting of Stockholders to be held at the Company's corporate office at 1550 West McEwen Drive, Suite 500, Franklin, Tennessee 37067, on Tuesday, June 10, 2025, at 9:00 a.m. Central Time. While we do not expect to make a separate presentation, we expect our directors and officers to be present at the Annual Meeting and available to respond to any questions you may have.

Your vote is very important to us. Whether or not you plan to attend the Annual Meeting, we urge you to vote your shares as promptly as possible. Details of the business to be conducted at the Annual Meeting are included in this Proxy Statement, which we encourage you to read carefully. You may submit your voting instructions over the Internet or by telephone as indicated on the enclosed proxy card or by completing, signing and dating the enclosed proxy card and returning it by mail in the accompanying envelope. If you plan to attend the Annual Meeting, please review the information on attendance provided in this Proxy Statement.

We would like to share with you several areas of particular significance in advance of our Annual Meeting and in connection with our distribution of this Proxy Statement:

2024 PERFORMANCE HIGHLIGHTS

As we reflect on 2024, we are proud of the efforts and dedication of our team and our performance, particularly our continued margin expansion, which was achieved in a highly complex market environment, as we continued to position Kaiser for the future. In addition, throughout the year, we remained steadfast in our commitment to meeting the evolving needs of our customers— a foundational principle that continues to drive our success.

Our 2024 net sales and conversion revenue of $3.02 billion and $1.46 billion, respectively, met our expectations, despite navigating a highly complex and rapidly changing market environment. Additionally, we were pleased to report 2024 net income of $66 million, or $4.02 per diluted share, along with adjusted earnings before interest, taxes, depreciation, and amortization (adjusted EBITDA) of $241 million. This resulted in a strengthened adjusted EBITDA margin (which is calculated as adjusted EBITDA as a percentage of conversion revenue) over the prior year. Effective January 1, 2025, we elected to change our method of accounting for certain inventory from the last-in, first-out ("LIFO") method to the weighted average cost ("WAC") method to improve the comparability of our operational results between periods by removing LIFO income or charge in a period resulting from LIFO valuation and changes to historical LIFO layers. This change has been retrospectively applied to the financial information presented in this Letter to our Stockholders. Please refer to “Appendix A” of this Proxy Statement for reconciliations of measures from generally accepted accounting principles (“GAAP”) measures to non-GAAP measures such as conversion revenue, adjusted EBITDA and adjusted EBITDA margin.

As a key supplier of highly engineered solutions used in diverse end market applications including aerospace and high-strength, packaging, general engineering, automotive extrusions, and other industrial applications, our niche areas of focus have only strengthened our competitive position. While each of our end markets presented unique challenges in 2024, we responded with resilience and determination, working diligently to meet the growing demand from our customers. At Kaiser, maintaining long-term customer relationships goes beyond high-quality products, on-time delivery, and superior customer satisfaction. It is rooted in a deep understanding of our customers’ evolving needs, including positively contributing to their approaches to sustainability. The mutual commitments we have built with our customers over the years serve as a foundation for guiding our business decisions and priorities.

In response to these growing needs, in 2020 we initiated a significant multi-year investment cycle across our portfolio, which we believe positions the Company to seize future opportunities and sustain our momentum for continued growth. These investments included upgrading our acquired Warrick rolling mill to convert approximately 25% of our existing mix to higher-margin coated products for packaging customers. Further, we are expanding capacity at our Trentwood rolling mill by approximately 5% to support anticipated stronger demand for high-value flat-rolled products for aerospace and general engineering applications. This investment is the start of our next major Phase VII expansion at Trentwood.

CORPORATE VALUES & SUSTAINABILITY

Our corporate values of being a preferred investment, a preferred supplier, a preferred employer, a preferred customer, and a valued corporate citizen define how we pursue sustainable business value and serve as the foundation of our culture and strategy. In 2024, we:

•

Enhanced our position as apreferred investment by continuing to deliver long-term shareholder value through disciplined capital allocation, including continued investment in our business to support our growth with $181 million of capital expenditures, the return of $51 million to our stockholders through our quarterly dividend payments, ongoing board refreshment and succession planning, executive compensation practices designed to align management with long-term growth and stockholder interests, proactively engaging with key stakeholders and maintaining our corporate governance best practices;

•

Advanced our position as apreferred supplier by providing a best-in-class customer experience, differentiating the Company through our broad Kaiser Select® line of products, including launching a new product line –Kaiser Select® Next Gen, providing products with superior consistency resulting in better performance and lower waste, remaining on track to achieve our 2030 GHG emissions intensity reduction targets and actively collaborating with our customers, suppliers, and industry partners to promote recycling and increase our use of recycled aluminum;

•

Strengthened our position as apreferred employerby continuing to focus on employee safety, resulting in continued strong safety performance, enhancing our recruitment, development, promotion, and retention strategies to attract qualified employees from all cultures and segments of the population and cultivating and promoting the next generation of leaders;

•

Maintained our position as apreferred customer through our continued partnership with our suppliers to meet our quality standards, material requirements, and commitments to customers and stakeholders and communication through our Supplier Code of Conduct of our expectations for compliance with all laws and regulations, ethical business practices, responsible sourcing of conflict minerals, and the sustainable management of natural resources; and

•

Furthered our position as avalued corporate citizen by actively engaging with local stakeholders to understand and address pressing community issues, offering both financial and in-kind support in the communities where we live and operate.

SUMMARY

In summary, we are extremely proud of the work our team has done to position the Company for an expected significant performance inflection, while remaining steadfast in our commitment to meet our customers’ needs. Looking ahead, we anticipate a stabilization in market conditions with all of our markets presenting strong, secular growth opportunities. We are eager for our stakeholders to benefit from the largest capital investment cycle in Kaiser’s recent history and are excited to bring key investments online to meet growing market demand. We remain confident in our ability to achieve sustainable, long-term growth, guided by our five corporate values.

We are committed to managing our business for long-term success in a way that is economically, environmentally, and socially responsible, ensuring that we remain a good corporate citizen and a steward of both capital and resources. Thank you to our stockholders, our employees and their families, our customers, our suppliers and our other stakeholders for their ongoing commitment to and support of Kaiser Aluminum.

1550 West McEwen Drive, Suite 500

Franklin, Tennessee 37067

NOTICE OF ANNUAL MEETING OF STOCKHOLDERS

TO BE HELD ON June 10, 2025

NOTICE IS HEREBY GIVEN that the 2025 Annual Meeting of Stockholders (the "Annual Meeting") of Kaiser Aluminum Corporation (the "Company") will be held at the Company's corporate office, located at 1550 McEwen Drive, Suite 500, Franklin, Tennessee 37067, on Tuesday, June 10, 2025, at 9:00 a.m., Central Time, for the following purposes:

(1)

To elect three members to our board of directors for three-year terms to expire at our 2028 annual meeting of stockholders;

(2)

To approve, on a non-binding, advisory basis, the compensation of our named executive officers as disclosed in the accompanying Proxy Statement;

(3)

To ratify the selection of Deloitte & Touche LLP as our independent registered public accounting firm for 2025; and

(4)

To consider such other business as may properly come before the Annual Meeting or any adjournments thereof.

Information concerning the matters to be acted upon at the Annual Meeting is set forth in the accompanying Proxy Statement. This notice and the accompanying proxy materials are being mailed or made available to stockholders on or about April 28, 2025.

The close of business on April 17, 2025 has been fixed as the record date for determining the stockholders entitled to notice of, and to vote at, the Annual Meeting or any adjournments thereof.

We urge stockholders to vote by proxy by submitting voting instructions over the Internet or by telephone as indicated on the enclosed proxy card or by completing, signing and dating the enclosed proxy card and returning it by mail in the accompanying envelope, which does not require postage if mailed in the United States.

By Order of the Board of Directors

John M. Donnan

Executive Vice President, Chief Administrative

Officer and General Counsel

April 28, 2025

Franklin, Tennessee

PROPOSALS AND BOARD RECOMMENDATIONS

Proposal 1 - Election of Directors

The board of directors recommends a vote "FOR ALL" of the persons nominated by the board of directors.

Additional information about each director and his and her qualifications may be found beginning on page 5.

Proposal 2 - Advisory Vote to Approve Named Executive Officer Compensation

The board of directors recommends a vote "FOR" the approval, on a non-binding, advisory basis, of the compensation of our named executive officers as disclosed in this Proxy Statement.

Additional information about executive compensation may be found beginning on page 12.

Proposal 3 - Ratification of Appointment of Independent Registered Public Accounting Firm

The board of directors recommends a vote "FOR" the ratification of the audit committee's selection of Deloitte & Touche LLP as our independent registered public accounting firm for 2025.

Additional information about the independent registered public accounting firm may be found beginning on page 15.

PROXY STATEMENT SUMMARY

In 2024, we delivered solid performance, including continued margin expansion, despite a highly complex and dynamic market environment. This summary highlights information contained elsewhere in this Proxy Statement but does not contain all of the information that you should consider. We encourage you to read the entire Proxy Statement for more information about these topics prior to voting.

(1)

Effective January 1, 2025, we elected to change our method of accounting for certain inventory from the LIFO method to the WAC method to improve the comparability of our operational results between periods. This accounting change has been retrospectively applied to the financial information presented in the 2024 Performance Highlights section.

(2)

See Appendix A of this Proxy Statement for reconciliations of measures from GAAP to non-GAAP. While our use of terms such as EBITDA, “adjusted” or "Conversion Revenue" is not intended to be (and should not be relied on) in lieu of the comparable captions under GAAP to which these metrics are reconciled, those terms are intended to provide greater clarity of the impact of certain material items on the GAAP measure and are not intended to imply those terms should be excluded.

i

EXECUTIVE COMPENSATION HIGHLIGHTS

Our incentive programs are designed to “pay for performance,” and it is expected that payouts may be impacted during difficult business/economic conditions. As described in further detail in the “Executive Compensation - Compensation Discussion and Analysis” section of this Proxy Statement, or CD&A, our 2024 compensation program was developed and designed to:

•

align the interest of our named executive officers and stockholders by tying a significant portion of compensation to enhancing total shareholder return ("TSR");

•

attract, motivate and retain highly experienced executives with significant industry experience vital to our short-term and long-term success, profitability and growth;

•

deliver a mix of fixed and at-risk compensation with the portion of compensation at risk increasing with seniority;

•

tie our executive compensation to our ability to pay and safety, quality, delivery, productivity and individual performance directly linked to our strategic initiatives; and

•

require strong financial performance as we continue to invest in our business.

In 2024, the compensation of our named executive officers consisted primarily of the following components:

•

a base salary (1) compensating each named executive officer based on the level and scope of responsibility, individual expertise and prior experience and (2) providing a fixed amount of cash compensation upon which our named executive officers can rely;

•

a short-term annual cash incentive (1) payable only if our company achieved certain Adjusted EBITDA, safety, quality, and delivery performance, (2) with positive and negative adjustments to individual awards, in exceptional instances, approved by our compensation committee, based on individual, facility, and/or functional area performance, as well as performance against other strategic initiatives, and (3) capped at 2.5 times target; and

ii

•

an equity-based, long-term incentive designed to align compensation with the interests of our stockholders and to enhance retention of our named executive officers consisting of (1) restricted stock units with three-year cliff vesting and (2) performance shares, which vest, if at all, based on our performance against demanding underlying metrics over the applicable three-year performance period.

Because grants under our long-term incentive program are outstanding for three years, at any time we have three over-lapping long-term incentive programs outstanding. The underlying metrics applicable to the performance shares can vary as our compensation committee assesses the effectiveness of our outstanding programs, metrics critical to our long-term success, feedback from our stockholders and compensation trends. The following table describes the performance share metrics (described more fully below) for our 2022-2024, 2023-2025 and 2024-2026 long-term incentive programs:

The compensation committee, working with its independent compensation consultant, Meridian Compensation Partners, LLC (referred to herein as Meridian), reviews, evaluates and updates our compensation peer group, which includes companies in both similar and different industries, at least annually. For 2024, the compensation committee approved a 23-company peer group more fully described in our CD&A section. Due to the differences in size among the companies in our peer group, Meridian uses a regression analysis to adjust survey data results based on our revenue as compared to the revenue of other companies in our peer group.

Pay for Performance

The table below summarizes the performance metrics under our 2024 short-term incentive plan ("2024 STI Plan") and 2024-2026 long-term incentive plan ("2024-2026 LTI Plan") for our named executive officers:

• Safety performance is measured using our total case incident rate ("TCIR") and lost-time case incident rate ("LCIR"). Quality performance is measured using our no-fault claim rate. Delivery performance is measured by our on-time delivery rate.

** As noted, the individual modifier is discretionary and, with respect to our executive officers, only used in exceptional instances approved by the compensation committee based on actual performance, including individual, facility and/or functional area performance, as well as performance against other strategic initiatives.

The following summarizes the key features and our performance against the metrics under our 2024 STI Plan and our 2022-2024 long-term incentive plan ("2022-2024" LTI Plan"):

2024 STI Plan

iii

The final multiplier of our 2024 STI Plan, including the impact of all performance metrics, was 0.95x. The table below summarizes the performance metrics and payout potential under our 2024 STI Plan and our performance against each of the metrics:

*Total may not sum due to rounding.

Annual Performance Award Payouts under Short-Term Incentive Plans for our Named Executive Officers

The chart on the right illustrates our annual Adjusted EBITDA performance multipliers for the last three years under our 2022, 2023 and 2024 short-term incentive plans before the application of modifiers for the 2022 short-term incentive plan and excluding the impact of the other performance metrics for the 2023 and 2024 short-term incentive plans. As previously discussed, effective January 1, 2025, we elected to change our method of accounting for certain inventory from the LIFO method to the WAC method to improve the comparability of our operational results between periods. This accounting change has not been retrospectively applied to the figures in the chart. Therefore, the reconciliation of Adjusted EBITDA on Appendix A of this Proxy Statement is not applicable. For purposes of awards under the applicable plans, Adjusted EBITDA means GAAP operating income excluding the impact of mark-to-market loss, restructuring costs, acquisition costs, goodwill impairment, non-cash asset impairment charges, other operating non-run-rate loss, depreciation and amortization.

The final multipliers of our 2022 and 2023 short-term incentive plans, after the application of modifiers and including the impact of the other performance metrics, were 0.00x and 0.86x, respectively. As discussed above, the final multiplier of our 2024 STI Plan, after taking into consideration of all performance metrics, was 0.95x.

2022-2024 LTI Plan

As discussed in more detail below, for the 2022 to 2024 performance period, the impact of challenging business conditions and operational challenges significantly and negatively impacted our ability to achieve the required level of performance for our Adjusted

iv

EBITDA margin performance metric under the 2022-2024 LTI Plan. Accordingly, no performance shares were earned based on our Adjusted EBITDA margin performance over the 2022-2024 performance period, while our relative TSR performance resulted in a total payout of 44% under the 2022-2024 LTI Plan.

Annual Performance Award Payouts under Long-Term Incentive Plans

The table below reflects our annual performance award payouts for the last three years under our completed long-term incentive plans.

Performance Share Award Payouts Based on Relative TSR

For our 2022-2024 LTI Plan, 60% of the performance shares granted to our named executive officers were subject to our TSR performance metric over the applicable three-year performance period compared to the TSR of the other companies comprising the S&P SmallCap 600 Materials and S&P MidCap 400 Materials Indices.

In considering constituents for the S&P SmallCap 600 Materials and S&P MidCap 400 Materials Indices, S&P Dow Jones Indices currently looks for companies (1) with market capitalization of between $1.1 billion and $7.4 billion and between $7.4 billion and $20.5 billion, respectively, (2) meeting certain float requirements, (3) with a U.S. domicile, (4) required to file Securities and Exchange Commission ("SEC") annual reports, and (5) listed on a major U.S. exchange, among other factors. The beginning and ending stock prices used to determine our TSR are calculated using the 20-trading day average preceding the beginning and end of the performance period. Based on our relative TSR performance for the 2022-2024 performance period, the multiplier for such metric was 74%, resulting in a final multiplier of 0.44x.

The chart below illustrates the relative TSR performance payout multipliers for our performance share awards under the 2020-2022, 2021-2023 and 2022-2024 long-term incentive programs:

Performance Share Award Payout Based on Adjusted EBITDA Margin

For our 2022-2024 LTI Plan, 40% of the performance shares granted to our named executive officers were subject to an Adjusted EBITDA margin performance metric, calculated by our Adjusted EBITDA as a percentage of conversion revenue over the three-year performance period. Our conversion revenue is calculated as our net sales less the hedged cost of alloyed metals.

v

For the 2022 to 2024 performance period, our adjusted EBITDA margin was negatively impacted by a number of factors, including (i) supply chain challenges, such as the impact of the declaration of force majeure by Warrick’s primary magnesium supplier and ultimately the cessation of all magnesium deliveries from that supplier that led to our declaration of force majeure at Warrick in 2022, (ii) molten metal supply issues that negatively impacted Warrick, (iii) the inflationary environment and significant corresponding increases in costs, (iv) a planned outage at Trentwood in 2022, and (v) a challenging labor market. As a result, despite our improved performance in 2023 and 2024, we did not achieve the threshold Adjusted EBITDA margin required for a payout and no performance shares were earned under the Adjusted EBITDA margin metric.

2024 Total CEO Compensation

As previously noted, the mix of our CEO’s total target compensation is heavily weighted toward performance-based compensation with more than 80% of the total target compensation being at-risk (short- and long-term compensation), more than 60% of the total target compensation being long-term, and 50% of the long-term target being allocated to performance shares.

The market pay analysis performed by Meridian at the end of 2024 reflected that the total target compensation of our CEO for 2024 was 13% below the median of our compensation peer group and that our CEO’s (1) base salary was approximately 5% below the median base salary, (2) short-term incentive target was approximately 9% below the median and (3) long-term incentive target was approximately 15% below the median. While stronger performance in 2024 resulted in a 0.95x payout to our CEO under our 2024 STI Plan, the payout to our CEO under our long-term incentive program was further impacted by the challenging business conditions and operational challenges described above during the 2022-2024 performance period, resulting in only 44% of the performance shares being earned. As previously discussed, although the payout under our long-term incentive program, including the payout to our CEO, was significantly impacted by the challenging business conditions and operational challenges, based on management’s recommendation, the compensation committee did not make any adjustments to our existing long-term incentive program or the underlying payout.

vi

1550 West McEwen Drive, Suite 500

Franklin, Tennessee 37067

PROXY STATEMENT

FOR

ANNUAL MEETING OF STOCKHOLDERS

To Be Held on June 10, 2025

TABLE OF CONTENTS

Important Notice Regarding the Availability of Proxy Materials for the Annual Meeting of Stockholders to be held on June 10, 2025: The Proxy Statement and our Annual Report to Stockholders are available at www.envisionreports.com/kalu.