ADVISORY/S1 Business Partners to Address Hundreds of Institutions at S1'S Catalyst 2002 Customer Forum.

News/Assignment Editors

ADVISORY...for Monday - Thursday (Sept. 30 - Oct. 3)

--(BUSINESS WIRE)

IBM, FinanCenter, KPMG Consulting, BEA, CheckFree and Sun

Microsystems Among Others Sponsor Industry Event

    WHO:    S1 Corporation, (Nasdaq: SONE), a leading global provider
            of Enterprise solutions for the financial services
            industry.

    WHAT:   Catalyst 2002 Customer Forum, themed "Potential. Progress.
            Payoff." This forum will equip S1 customers with
            information on the measurable value of their current
            systems and how to execute short- and long-term integration
            strategies. Most importantly, participants will gain
            insight into how they can obtain one view of each customer
            that will empower them to solidify profitable
            relationships across multiple channels, applications and
            segments.

    WHERE:  Westin Peachtree Plaza, Atlanta, Ga.

    WHEN:   September 30 - October 3, 2002

    This year more than 24 S1 partners are participating in Catalyst
2002 and joining the Company in creating a compelling forum for
financial institutions to learn how they can leverage new and existing
technologies and products to forge more profitable, long-term
relationships with their customers.

    This year's sponsors include:

    --  Diamond sponsor - IBM;

    --  Gold sponsors - FinanCenter and KPMG Consulting;

    --  Silver sponsors - BEA, CheckFree and Sun Microsystems;

    --  Bronze sponsors - Aurum Technology, Cisco, Metavante,
        Princeton eCom and SunGard;

    --  Additional sponsors - Addmaster, BankWare, Bisys Retirement
        Services, Clarke American, eClassic Systems, Edify, Intrieve,
        Intuit, Murphy & Company, PC4, PentaSafe, Spectrum and Unisys.

    In addition to participating in Catalyst, many S1 partners will
present at sessions being held throughout the three-day event. Partner
presentations include:

    --  Featured keynote Mark Lewis, vice president, financial
        services sector, Americas for IBM, will examine "Two
        Perspectives -- One Goal: Unrivaled Customer Loyalty" in
        collaboration with Cigdem Oktem, director of The Council on
        Financial Competition;

    --  Jerry Kita, consulting sales specialist, IBM will provide in a
        session titled, "Defining a Multi-Channel Strategy for Your
        Organization," an overview of cost-effective strategies for
        financial services providers to create a multi-channel
        approach to serving their customers and define
        customer-centricity; and,

    --  Sherri Neasham, founder and CEO, FinanCenter will deliver
        "Increase Banking Product Revenues With An Interactive Selling
        System," a discussion of the latest technology designed to
        allow banks and financial institutions of all sizes to
        increase their product revenues; and,

    --  Jeff Weikert, vice president, Electronic Commerce Division,
        CheckFree Corporation plans to present "Electronic Billing and
        Payment: Taking Convenience to Main Street" to walk S1
        customers through the latest best practices in electronic bill
        payment; and,

    --  Lenn Freeman, branch automation specialist, Aurum Technology
        will present "Aurum Technology and S1: Leveraging the Best of
        Both Worlds," an overview of the future of MISER(TM), Aurum
        Technology's core processing solution, and how Aurum is taking
        full advantage of S1 products through branch automation and
        CRM to improve service, enhance performance and ensure
        financial success in the session titled; and,

    --  Chris Simard, major account manager, Rod Scott, business
        development manager, and Jack Evans, customer solutions
        manager, Cisco Systems, will deliver "Branch of the Future,"

        Cisco's view of technological advances that can be made in the
        branch - the most critical channel in retail delivery.

For registration information, please visit www.s1catalyst.com or contact Priscilla Cross, S1 Corporation, 404-923-3500. For media inquiries, please contact Christopher Rogers, Sterling Hager, Inc., 617-393-4285.

About S1 Corporation

S1 (Nasdaq: SONE) is a leading global provider to more than 3,900 banks, credit unions, insurance providers, and investment firms of enterprise software solutions that create one view of customers across multiple channels, applications and segments. S1's Enterprise software solutions uniquely combine customer interaction and financial transaction capabilities, resulting in a more compelling experience for the customers and a more profitable relationship for the financial institution. S1 is the only provider with the proven experience, breadth of products, and financial strength to empower financial services companies' enterprise strategies. Additional information about S1 is available at www.s1.com.

Forward-Looking Statements

This press release contains forward-looking statements relating to results of operations; product features and benefits; market penetration and market strategies. Such statements are made based on management's beliefs as well as assumptions made by, and information currently available to, management, pursuant to "safe-harbor" provisions of the Private Securities Litigation Reform Act of 1995. While these statements reflect our best judgment, they are subject to risks and uncertainties that could cause a change in focus and direction. A discussion of certain risk factors that may cause actual results to differ from these forward-looking statements can be found in S1's Annual Report on Form 10-K for the period ended December 31, 2001, on file with the SEC.