ACI Worldwide Extends Timing Agreement With the DOJ for an Additional Ten Days; Extends Expiration Date for S1 Exchange Offer

ACI Worldwide, Inc.

announced today that it has extended its exchange offer for all of the outstanding shares of common stock of S1 Corporation

until 5:00 p.m., Eastern time, on Friday, February 10, 2012, unless further extended. As previously announced, ACI and S1 entered into an agreement with the U.S. Department of Justice (the "DOJ") in order to permit the DOJ additional time to review the information furnished by ACI and S1 under the U.S. premerger clearance laws (the "HSR Act"). That agreement provided that ACI and S1 would not close the transaction before January 31, 2012 without the DOJ's prior consent. The DOJ has not completed its review of the information provided by the parties and requested an extension of time beyond January 31, 2012. ACI and S1 agreed with the DOJ to extend the term of the agreement for ten days. Accordingly, ACI and S1 will not close the transaction prior to February 10, 2012 without the DOJ's prior consent. ACI and S1 have each certified their compliance with the DOJ's previously announced second request for information, and both companies continue to assist the DOJ in its review of that information. The DOJ's second request for information is focused on the card payments business. In 2010, S1's card payments business generated approximately $11.9 million in revenue in the United States.