144 0001247456 XXXXXXXX LIVE 0000075677 PACKAGING CORP OF AMERICA 001-15399 1 NORTH FIELD CT LAKE FOREST IL 60045 8474823000 KOWLZAN MARK W Member of immediate family of any of the foregoing Common Northern Trust Securities, Inc.

50 S Lasalle Street Chicago IL 60603

9266 1973102.04 89098647 05/27/2026 NYSE Common 02/23/2026 Stock Award Issuer N 9266 02/23/2026 Compensation Y Shares sold for the following trust account(s): MARK WILLIAM KOWLZAN REVOC TRUST U/A 1/24/06 05/27/2026 /s/ Heather Virgoe as a duly authorized representative of National Financial Services LLC, as attorney-in-fact for KOWLZAN MARK W