ACI Next Generation e-Payment Software Now Available on HP Integrity Servers Running HP-UX; Collaborative Effort Fosters Customer Migration toward Open Systems Technology.

OMAHA, Neb. -- ACI Worldwide (Nasdaq:TSAI), a leading international provider of enterprise e-payment solutions, today announced the availability of its BASE24-es(TM) e-payment software on the HP Integrity server family running the HP-UX 11i operating system. The offering delivers functions and features in an open systems environment to help customers improve operational costs and deployment efficiencies. The solution has already been licensed to a top 100 U.S. bank.

Representing the next generation of ACI's world class payments platform, BASE24-es offers an end-to-end solution to acquire, authenticate, route, switch and authorize electronic payment transactions across multiple delivery channels. BASE24-es allows banks, retailers and processors to improve profitability, enhance the customer experience and service, and improve time to market with new products. HP-UX 11i running on the HP Integrity server family delivers market-leading price/performance in a highly reliable, scalable and manageable environment.

"We are pleased to announce the availability of BASE24-es on the HP-UX 11i platform," said Jeffrey S. Hale, ACI Chief Marketing Officer. "This initiative broadens our long-standing relationship with HP, and offers our customers even more choice as they seek to respond to an extremely competitive environment in a cost-effective way. HP's commitment to price/performance, systems reliability and market-leading quality is very well-aligned to our customers' needs in the enterprise e-payments marketplace. Our customers demand 'financial dialtone' levels of service and availability, as consumers continue to increase their use of electronic payments technology, moving away from cash and checks. Together, HP and ACI address that demand."

"HP is working with ACI to offer financial services customers an innovative architecture for next-generation e-payments on HP's leading UNIX platform," said Tim Evans, worldwide director, banking, Financial Services Industry, HP. "Customers will benefit from our combined offering with an optimal balance of scale, reliability, manageability and price/performance."

About ACI Worldwide

Every second of every day, consumers are initiating electronic payment transactions--getting cash at ATMs, using debit and credit cards to make purchases in stores and on the Internet, banking by phone and PC, paying bills online. Over 40 billion times a year, ACI software is used to process these transactions, powering the world's online payment systems. ACI was founded in 1975 and pioneered the development of applications and networking software for online transaction processing. Today more than 500 customers in 76 countries use ACI supplied software. Visit ACI Worldwide on the Internet at www.aciworldwide.com.

Any statements in this press release regarding projected results are preliminary and "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995. In addition, this press release may contain other forward-looking statements including statements regarding Transaction Systems Architects, Inc.'s ("TSA"), its subsidiaries or third parties' expectations, predictions, views, opportunities, plans, strategies, beliefs, and statements of similar effect. The forward-looking statements in this press release are subject to a variety of risks and uncertainties. Actual results could differ materially.

For a detailed discussion of these and other risk factors, interested parties should review the Company's filings with the Securities and Exchange Commission, including the Company's Form 10-K filed on December 23, 2003, the Company's Form 10-Q filed on February 17, 2004, the Company's Form 10-Q filed on May 17, 2004, and the Company's Form 10-Q filed on August 11, 2004.