X0407 4 2023-06-01 0 0000811596 KAISER ALUMINUM CORP KALU 0001801065 Weaver Brant 1550 WEST MCEWEN DRIVE SUITE 500 FRANKLIN TN 37067 0 1 0 0 VP - Strategic Development 0 Common Stock, par value $0.01 per share 2023-06-01 4 F 0 716 62.60 D 7337 D Shares withheld to satisfy the withholding tax obligations resulting from the vesting on June 1, 2023 of certain restricted stock units granted to the reporting person in 2018 under the Kaiser Aluminum Corporation 2016 Equity and Incentive Compensation Plan. Includes 4,258 shares acquired pursuant to grants of restricted stock units. /s/ Cherrie I. Tsai, with power of attorney for Brant Weaver 2023-06-02