PACKAGING CORP OF AMERICA Stock Compensation Disclosure

The Company has a long-term equity incentive plan, which allows for grants of restricted stock, performance awards, stock appreciation rights, and stock options to directors, officers, and employees, as well as others who engage in services for PCA. On February 28, 2024, our board of directors approved, and, on May 8, 2024, our stockholders approved, the amendment and restatement of the plan. The amendment extended the plan’s term to May 8, 2034 and increased the number of shares of common stock available for issuance under the plan by 2.4 million shares. The total number of shares authorized for past and future awards is 14.3 million shares.

As of December 31, 2025, assuming performance units are paid out at the target level of performance, 2.5 million shares were available for future grants under the current plan. Forfeitures are added back to the pool of shares of common stock available to be granted at a future date.

Restricted Stock

Restricted stock awards granted to officers and employees generally vest at the end of a four-year period, and restricted stock awards granted to directors vest immediately. A summary of the Company’s restricted stock activity follows:

Performance Units

Performance unit awards granted to certain officers are earned based on the achievement of defined performance rankings of Return on Invested Capital (ROIC) or Total Shareholder Return (TSR) compared to ROIC and TSR for peer companies. ROIC performance unit awards vest four years after the grant date, while TSR performance unit awards vest approximately three years after the grant date. Both ROIC and TSR performance units are paid out entirely in shares of the Company’s common stock. A summary of the Company’s performance unit activity follows:

Compensation Expense

The fair value of restricted stock is determined based on the closing price of the Company’s stock on the grant date. Compensation expense, net of estimated forfeitures, is recorded over the requisite service period. As PCA’s Board of Directors has the ability to accelerate the vesting of these awards upon an employee’s retirement, the Company accelerates the recognition of compensation expense for certain employees approaching normal retirement age.

For performance unit awards made in 2025, 2024, and 2023, in terms of grant date value, 50% used total shareholder return (TSR) as the performance measure and 50% used return on invested capital (ROIC) as the performance measure. All units awarded before 2018 used ROIC as the performance measure. The ROIC component of performance unit awards is valued based on the closing price of the stock on the grant date. As the ROIC component contains a performance condition, compensation expense, net of estimated forfeitures, is recorded over the requisite service period based on the most probable number of awards expected to vest. The TSR component of performance unit awards is valued using a Monte Carlo simulation as the TSR component contains a market condition. The Monte Carlo simulation estimates the fair value of the TSR component based on the expected term of the award, a risk-free interest rate, expected dividends, and expected volatility of the Company’s common stock and the common stock of the peer companies. Compensation expense is recorded ratably over the expected term of the award regardless of whether the market condition is satisfied.

We evaluate share-based compensation expense on a quarterly basis based on our estimate of expected forfeitures, review of recent forfeiture activity, and expected future turnover. We recognize the effect of adjusting the forfeiture rate for all expense amortization in the period that we change the forfeiture estimate. The effect of forfeiture adjustments was insignificant in all periods presented.