X0306 4 2023-03-05 0 0000811596 KAISER ALUMINUM CORP KALU 0001769865 Huey Jennifer 1550 WEST MCEWEN DRIVE SUITE 500 FRANKLIN TN 37067 0 1 0 0 VP & Chief Accounting Officer Common Stock, par value $0.01 per share 2023-03-05 4 A 0 2473 0.00 A 8242 D Common Stock, par value $0.01 per share 2023-03-05 4 F 0 304 84.33 D 7938 D Grant to the reporting person effective as of March 5, 2023 of restricted stock units under the Kaiser Aluminum Corporation 2021 Equity and Incentive Compensation Plan. All restrictions will lapse on March 5, 2026 or earlier upon the occurrence of certain specified circumstances. Includes 7,326 shares acquired pursuant to grants of restricted stock units. Shares withheld to satisfy the withholding tax obligations resulting from the vesting on March 5, 2023 of certain restricted stock units granted to the reporting person in 2020 under the Kaiser Aluminum Corporation 2016 Equity and Incentive Compensation Plan. Includes 6,581 shares acquired pursuant to grants of restricted stock units. /s/ Cherrie I. Tsai, with power of attorney for Jennifer Huey 2023-03-07