X0306 4 2023-02-22 0 0000075677 PACKAGING CORP OF AMERICA PKG 0001247456 KOWLZAN MARK W 1 N. FIELD COURT LAKE FOREST IL 60045 1 1 0 0 Chairman & CEO Common Stock 2023-02-22 4 A 0 23765 0.00 A 484545 D Common Stock 2023-02-22 4 A 0 19303 0.00 A 503848 D Common Stock 2565 I by spouse Common Stock 18015 I 401k plan Award of restricted stock. On February 22, 2023, the Section 162(m) subcommittee of the compensation committee of the registrant's board of directors certified attainment of the performance measure under the performance units awarded to reporting person on June 28, 2019. Performance was achieved at the 100% level, which will result in the reported number of shares being paid out on June 28, 2023, the vesting date of the units, subject to continued service by the reporting person through such date. Reporting person disclaims beneficial ownership of shares held by spouse. Kent A. Pflederer, attorney in fact 2023-02-24