KAISER ALUMINUM CORP

For the year ended December 31, 2024, (1) the annual total compensation of Mr. Harvey, our CEO, was $6,628,487 (the same amount as reported for him for 2024 in the Summary Compensation Table above); (2) the annual total compensation of our median employee (defined below) was $83,577; and (3) the resulting ratio of the annual total compensation of our CEO to the median of the annual total compensation of all of our employees and those of our consolidated subsidiaries (other than Mr. Harvey) was 79:1. This ratio is a reasonable estimate calculated in a manner consistent with Item 402(u) of Regulation S-K using the data and assumptions summarized above. The assumptions we used are specific to our company and our employee population. As a result, our pay ratio may not be comparable to the pay ratios of other companies. The total compensation of the median employee for the year ended December 31, 2024 was determined in the same manner as the total compensation shown for Mr. Harvey in the 2023 Summary Compensation Table.

There has been no change in our employee population or employee compensation arrangements in fiscal year 2023 that we believe would significantly impact the pay ratio disclosure. As a result, under instruction 2 to Item 402(u) of Regulation S-K, we are permitted to use the same median employee identified for 2022 for purposes of this disclosure.

We identified our median employee using the following methodology:

•

we prepared a list of all employees as of December 31, 2022, which is our determination date;

•

we applied a Canadian to U.S. dollar exchange rate for compensation paid in Canadian currency using the exchange rate in effect as of December 31, 2022;

•

we ranked the annual gross income of all employees for the year ended December 31, 2022, except for Mr. Harvey, using the Form W-2 compensation for our U.S. employees and Form T4 compensation for our Canadian employees; and

•

we selected the employee with the median annual gross income (our "median employee").