Press Release

Transaction Systems Architects Completes Initial Closing of eps Acquisition

May 31, 2006

The Company also announced today that its Board of Directors has approved an increase of $30 million to its stock repurchase plan, bringing the total of the approved plan to $110 million.

From the inception of the Company’s stock repurchase plan through May 30, 2006, the Company has repurchased a total of 2,123,161 shares for approximately $53.4 million.

Notes to editors

About Transaction Systems Architects, Inc.
The Company’s software facilitates electronic payments by providing consumers and companies access to their money.  Its products are used to process transactions involving credit cards, debit cards, secure electronic commerce, mobile commerce, smart cards, secure electronic document delivery and payment, checks, high-value money transfers, bulk payment clearing and settlement, and enterprise e-infrastructure.  The Company’s solutions are used on more than 1,960 product systems in 83 countries on six continents. Visit Transaction Systems Architects, Inc. on the Internet at www.tsainc.com.

Investor Contacts

John Kraft, Head of Strategy & Finance
Email: john.kraft@aciworldwide.com

Global Headquarters:
ACI Worldwide
2811 Ponce de Leon Blvd, PH1
Coral Gables, FL 33134