Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2018 Commission File Number 0-25346 ACI WORLDWIDE, INC. (Exact name of registrant as specified in its charter) Delaware 47-0772104 (State or other jurisdiction of incorporation or organization)(I.R.S. Employer Identification No.) 3520 Kraft Rd, Suite 300 Naples, FL 34105 (239) 403-4600 ( ...