X0306 4 2023-03-05 0 0000811596 KAISER ALUMINUM CORP KALU 0001551870 Parkinson Ray 1550 WEST MCEWEN DRIVE SUITE 500 FRANKLIN TN 37067 0 1 0 0 SVP - Advanced Engineering Common Stock, par value $0.01 per share 2023-03-05 4 A 0 1931 0.00 A 9596 D Common Stock, par value $0.01 per share 2023-03-05 4 A 0 10000 0.00 A 19596 D Common Stock, par value $0.01 per share 2023-03-05 4 F 0 644 84.33 D 18952 D Common Stock, par value $0.01 per share 7333 I By Family Trust 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 6,811 shares acquired pursuant to grants of restricted stock units. Includes 16,811 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 15,126 shares acquired pursuant to grants of restricted stock units. /s/ Cherrie I. Tsai, with power of attorney for Raymond Parkinson 2023-03-07