ACI Worldwide Extends Expiration Date for S1 Exchange Offer to November 30, 2011

ACI Worldwide, Inc. ACIW announced today that it has extended its exchange offer for all of the outstanding shares of common stock of S1 Corporation SONE until 5:00 p.m., Eastern time, on Wednesday, November 30, 2011, unless further extended. On October 3, 2011, ACI agreed to acquire S1 for approximately $360 million in cash and 5.8 million ACI shares. Under the terms of the transaction, S1 stockholders may elect to receive $10.00 in cash or 0.3148 shares of ACI stock for each S1 share they own, subject to proration, such that in the aggregate 33.8% of S1 shares are exchanged for ACI shares and 66.2% are exchanged for cash.