Shareholder Vote

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549     FORM 8-K     CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of report (Date of earliest event reported): May 12, 2026     Packaging Corporation of America (Exact name of registrant as specified in its charter)       Delaware   1-15399   36-4277050 (State or other jurisdiction of incorporation)   (Commission File Number)   (IRS Employer Identification No.) 1 N. Field Court , Lake Forest , Illinois 60045 (Address of Principal Executive Offices, including Zip Code) (847) 482-3000 (Registrant’s Telephone Number, Including Area Code)     Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrants under any of the following provisions:   ☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)   ☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)   ☐ Pre-commencement communications pursuant to Rule 14d-2 (b) under the Exchange Act (17 CFR 240.14d-2 (b))   ☐ Pre-commencement communications pursuant to Rule 13e-4 (c) under the Exchange Act (17 CFR 240.13e-4 (c)) Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter). Emerging growth company ☐ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐ Securities registered pursuant to Section 12(b) of the Exchange Act:   Title of each class   Trading Symbol(s)   Name of each exchange on which registered Common Stock   PKG   New York Stock Exchange       Item 5.07. Submission of Matters to a Vote of Security Holders On May 12, 2026, Packaging Corporation of America (“PCA”) held its 2026 Annual Meeting of Stockholders, at which the following proposals were voted upon and approved by PCA’s stockholders: (a)  Election of Directors . Voting results are summarized as follows:   Nominee    Votes For      Votes Against      Abstentions      Broker Non-Vote   Cheryl K. Beebe      74,535,448        5,009,056        41,399        3,975,507   Duane C. Farrington      78,947,264        561,789        76,850        3,975,507   Karen E. Gowland      78,119,832        1,370,588        95,483        3,975,507   Donna A. Harman      78,940,200        572,065        73,638        3,975,507   Mark W. Kowlzan      77,154,503        2,387,938        43,462        3,975,507   Robert C. Lyons      78,012,659        1,494,605        78,639        3,975,507   Samuel M. Mencoff      67,878,835        8,681,658        3,025,410        3,975,507   Roger B. Porter      64,678,389        11,849,812        3,057,702        3,975,507   Thomas S. Souleles      75,213,947        4,291,228        80,728        3,975,507   (b)  Ratification of Independent Registered Public Accounting Firm . The audit committee’s appointment of KPMG LLP as PCA’s independent registered public accounting firm was ratified by the following vote: 82,796,126 votes for, 744,560 votes against, and 20,724 abstentions. (c)  Approval of PCA’s Executive Compensation : 76,265,206 votes for, 2,299,022 votes against, 1,021,675 abstentions and 3,975,507 broker non-votes.   SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.   PACKAGING CORPORATION OF AMERICA By:   /s/ S. Ellis Cunningham   Vice President and General Counsel Date: May 13, 2026