PACKAGING CORP OF AMERICA (PKG) · Insider Trading (Form 4) SEC Filing

=== SEC Form 4 — Statement of Changes in Beneficial Ownership === Document Type: 4 Period of Report: 2026-03-27 10b5-1 Pre-arranged Plan: No --- Issuer --- Name: PACKAGING CORP OF AMERICA (PKG) CIK: 0000075677 --- Reporting Owner --- Name: Shirley Donald R. CIK: 0001776032 Role: Officer (Exec. VP) --- Non-Derivative Transactions --- [Transaction #1] Security: Common Stock Date: 2026-03-27 | Code: A (Grant or award) Shares: +6,254 | Price: $0.00 Shares Owned After: 33,282 | Ownership: D (Direct) Footnotes: [F1] On March 27, 2026, the compensation subcommittee of the compensation committee of the registrant's board of directors certified attainment of the performance measure under the TSR performance units awarded to the reporting person on February 22, 2023. Performance was achieved at 200%. The units paid out on the date of certification. [Transaction #2] Security: Common Stock Date: 2026-03-27 | Code: A (Grant or award) Shares: +478 | Price: $0.00 Shares Owned After: 33,760 | Ownership: D (Direct) Footnotes: [F2] Payout in shares of accumulated dividends on vesting performance units. [Transaction #3] Security: Common Stock Date: 2026-03-27 | Code: F (Payment of exercise/tax) Shares: -2,650 | Price: $212.25 Total Value: $562,462.50 Shares Owned After: 31,110 | Ownership: D (Direct) Footnotes: [F3] Pursuant to the terms of the Company's Long-Term Equity Incentive Plan, the Company withheld shares to cover the withholding tax obligation associated with equity awards vesting on the transaction date. --- Holdings --- [Holding #1] Security: Common Stock Ownership: I (Indirect) --- Footnotes (Complete Index) --- F1: On March 27, 2026, the compensation subcommittee of the compensation committee of the registrant's board of directors certified attainment of the performance measure under the TSR performance units awarded to the reporting person on February 22, 2023. Performance was achieved at 200%. The units paid out on the date of certification. F2: Payout in shares of accumulated dividends on vesting performance units. F3: Pursuant to the terms of the Company's Long-Term Equity Incentive Plan, the Company withheld shares to cover the withholding tax obligation associated with equity awards vesting on the transaction date. --- Signature --- /s/ Kent A. Pflederer, attorney in fact (2026-03-31)