ACI Worldwide Inc. is an American payment systems company headquartered in Elkhorn, Omaha, Nebraska. ACI develops a broad line of software focused on facilitating real-time electronic payments. ACI Worldwide's products and services are used globally by banks, financial intermediaries such as third-party electronic payment processors, payment associations, switch interchanges, merchants, corporations, and a wide range of transaction-generating endpoints, including automated teller machines, merchant point of sale terminals, bank branches, mobile phones, tablet computers, corporations, and internet commerce sites. Wikipedia