GPK: Other company developments

Item 8.01. Other Events. On August 14, 2026, a purported stockholder of Graphic Packaging Holding Company (“GPHC”) filed a derivative lawsuit against GPHC and certain current and former officers and directors as individual defendants (the “August 2026 Derivative Action”). The August 2026 Derivative Action asserts claims for violations of federal securities laws and for breach of fiduciary duty, aiding and abetting breach of fiduciary duty, waste of corporate assets and unjust enrichment. The allegations set forth and relief sought in the August 2026 Derivative Action are substantially similar to the allegations and relief sought in the June 2026 derivative action filed against GPHC and certain current and former officers and directors as previously disclosed in GPHC’s Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2026. GPHC intends to vigorously defend against the claims in the August 2026 Derivative Action. - 2 - SIGNATURE 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. By: /s/ Daniel S. Fishbein Daniel S. Fishbein Date: August 17, 2026 Executive Vice President, General Counsel and Secretary - 3 -