Chinatrust Commercial Bank to Fight Credit Card Fraud With Solution from ACI Worldwide.

OMAHA, Neb.--(BUSINESS WIRE)--Sept. 20, 1999--

ACI Worldwide (Nasdaq: TSAI), a leading international provider of enterprise electronic payments solutions, announces the licensing of its PRISM(R) fraud management system to Chinatrust Commercial Bank, Taiwan's largest private bank. Chinatrust will use PRISM to monitor and control credit card fraud.

Chinatrust Commercial Bank is the largest credit card issuer in Taiwan and chose PRISM to monitor fraudulent transactions within its portfolio of 1.6 million cardholders. PRISM will integrate with Chinatrust's BASE24(R) processing engine, also from ACI, to offer an integrated solution that acquires, authorizes and switches transactions while monitoring those transactions for fraud.

PRISM offers Chinatrust an advanced neural net-based fraud detection system that identifies subtle patterns of fraudulent behavior by comparing individual card and account usage with known patterns of fraud. Transactions are monitored in near real-time or batch environments and when a suspicious transaction is found, the transaction is flagged for prompt and appropriate action. PRISM's ability to recognize fraudulent activity and learn from experience provides a proactive method to reduce losses from fraud.

"PRISM enables Chinatrust to offer its cardholders an extra level of fraud protection while efficiently processing their transactions," said Don McLarty, vice president and managing director of ACI Worldwide's Asia/Pacific operation. "And, since PRISM integrates with Chinatrust's BASE24 system, the bank has the ability to handle increasing transaction volumes generated by its card base while monitoring those transactions for current and emerging fraudulent schemes."

PRISM includes patented technology provided by Nestor, Inc. (OTC: NEST) and is supported and distributed around the globe by ACI Worldwide.

ACI Worldwide (Nasdaq: TSAI) is helping customers change the way the world works with software products developed for consumer banking, corporate banking, retail and system solutions. The company maintains operations in the Americas, Europe/Middle East/Africa and Asia/Pacific and is a leading international provider of software for electronic commerce and electronic payments. ACI Worldwide distributed solutions are used by more than 2,100 customers in 76 countries. Visit ACI Worldwide on the Internet at www.aciworldwide.com.

This press release contains forward-looking statements made pursuant to the "safe harbor" provisions of the Private Securities Litigation Reform Act of 1995. You are cautioned that such forward-looking statements are not guarantees of future performance and involve risks and uncertainties that could significantly affect expected results in the future from those expressed in any such forward-looking statements made by, or on behalf of the company. Certain factors that could cause actual results to differ materially are contained in Exhibit 99.01 of the Transaction Systems Architects, Inc. Annual Report on form 10-K.