X0306 4 2021-03-22 0 0001810182 ALX ONCOLOGY HOLDINGS INC ALXO 0001816977 Pons Jaume C/O ALX ONCOLOGY HOLDINGS INC. 866 MALCOLM ROAD, SUITE 100 BURLINGAME CA 94010 1 1 0 0 President and CEO Common Stock 2021-03-22 4 M 0 16700 1.91 A 568046 D Common Stock 2021-03-22 4 S 0 1200 63.7875 D 566846 D Common Stock 2021-03-22 4 S 0 900 64.9846 D 565946 D Common Stock 2021-03-22 4 S 0 600 66.325 D 565346 D Common Stock 2021-03-22 4 S 0 1500 67.1823 D 563846 D Common Stock 2021-03-22 4 S 0 2700 68.27 D 561146 D Common Stock 2021-03-22 4 S 0 9200 69.7671 D 551946 D Common Stock 2021-03-22 4 S 0 600 70.1243 D 551346 D Employee Stock Option (right to buy) 1.91 2021-03-22 4 M 0 16700 0.00 D 2029-09-12 Common Stock 16700 89019 D The sale reported in this Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on January 28, 2021. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $63.33 to $64.25, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (2) through (8) to this Form 4. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $64.64 to $65.25, inclusive. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $65.80 to $66.69, inclusive. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $66.81 to $67.79, inclusive. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $67.81 to $68.80, inclusive. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $68.97 to $69.95, inclusive. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $70.00 to $70.20, inclusive. The option is subject to an early exercise provision and is immediately exercisable. Shares subject to the option vest in 48 equal monthly installments beginning on June 16, 2019. /s/ Peter Garcia, by power of attorney 2021-03-24