X0407 4 2023-06-07 0 0000811596 KAISER ALUMINUM CORP KALU 0001502941 Sebastian Teresa Mosley 1550 WEST MCEWEN DRIVE SUITE 500 FRANKLIN TN 37067 1 0 0 0 0 Common Stock, par value $0.01 per share 2023-06-07 4 A 0 2060 0.00 A 3385 D Common Stock, par value $0.01 per share 2023-06-07 4 A 0 356 63.08 A 3741 D Common Stock, par value $0.01 per share 4499 I By Truxton Trust Grant to the reporting person of restricted stock under the Kaiser Aluminum Corporation 2021 Equity and Incentive Compensation Plan. All restrictions will lapse on June 7, 2024. Stock received by the reporting person under the Kaiser Aluminum Corporation 2021 Equity and Incentive Compensation Plan at such person's election in lieu of all or a portion of the reporting person's annual cash retainer for serving as a member of the Board of Directors of Kaiser Aluminum Corporation and chair or a member of one or more committees of the Board of Directors. Equal to the average closing price of the Issuer's common stock as reported by the Nasdaq Stock Market, LLC for the twenty trading days prior to June 7, 2023. /s/ Cherrie I. Tsai, with power of attorney for Teresa M. Sebastian 2023-06-09