S1 Corporate Banking is Selected by Zions Bancorporation

Zions Family of Banks Chooses S1 Corporate Banking to Deliver Best-of-Class
Online Treasury Management Solution

NORCROSS, Ga., May 27, 2009 /PRNewswire-FirstCall/ -- S1 Enterprise, a
division of S1 Corporation (Nasdaq: SONE) and a leading global provider of
multichannel financial services software, today announced that Zions
Bancorporation will deploy S1 Corporate Banking to deliver a single
feature-rich online solution to its corporate banking customers.

Zions selected S1 for its innovative product functionality, leading edge
technology, and premier customer service. Zions' goal is to exceed its
treasury management clients' expectations with a new online experience,
focusing on the system's ease-of-use and depth of functionality. Zions' new
solution will offer users more flexibility and provide the ability to
customize the user experience. The system provides numerous payment options
for high and low value payments. Additionally, the offering will include
comprehensive security and risk management features.

"The synergy we felt with S1 was important. We wanted to partner with a
software provider who demonstrates an innovative spirit as well as proven
implementation success," said Debra J. Innes, EVP/Manager, Corporate Treasury
Management of Zions Bancorporation. "In addition, S1's collaborative product
development approach was a key criterion. We feel the S1 Corporate Banking
team demonstrates market and implementation responsiveness critical for us to
offer a compelling solution to our corporate clients across all of Zions
Bancorporation's affiliate banks."

"We have extensive experience implementing sophisticated solutions with the
innovative functionality large banks are seeking," said Fred Dumas, General
Manager, S1 Treasury Online Group. "Zions and S1 have a long, successful
relationship in the consumer, small business, and branch space. We are
excited that Zions has selected S1 Corporate Banking to serve as an integral
part of its online strategy for corporate customers and look forward to
extending our partnership."

S1 has twenty years of experience providing cash management solutions to the
world's largest banks. S1 Corporate Banking provides an integrated global
payments framework supporting diverse domestic and international payments,
including wire transfers, account transfers, ACH and localized payments for
over twenty countries. In addition to comprehensive payment services, S1
Corporate Banking offers a rich, highly flexible user-interface, extensive
security and entitlement features like multi-factor authentication, bulk file
transfers, check services, and complete information reporting supporting cash
position management.

About S1 Enterprise
More than 100 banks and three million consumer, small business, and corporate
users worldwide rely on S1 Enterprise solutions to access and manage their
financial information. A division of S1 Corporation (Nasdaq: SONE), S1
Enterprise is a leading global provider of integrated banking solutions that
deliver financial service providers a holistic view of their customers whether
online, in the branch or in the call center. Additional information about S1
Enterprise is available at www.s1enterprise.com.

About S1 Corporation
S1 Corporation (Nasdaq: SONE) delivers customer interaction software for
financial and payment services and offers unique solution sets for financial
institutions, retailers, and processors under three brand names: Postilion, S1
Enterprise and FSB Solutions. Additional information about S1 solutions is
available at www.s1.com, www.postilion.com, www.s1enterprise.com and
www.fsb-solutions.com.

About Zions Bancorporation
Zions Bancorporation is one of the nation's premier financial services
companies, consisting of a collection of great banks in select high growth
markets. Zions operates its banking businesses under local management teams
and community identities through approximately 500 offices in 10 Western and
Southwestern states: Arizona, California, Colorado, Idaho, Nevada, New Mexico,
Oregon, Texas, Utah and Washington. The company is a national leader in Small
Business Administration lending and public finance advisory services. In
addition, Zions is included in the S&P 500 and NASDAQ Financial 100 indices.
Investor information and links to subsidiary banks can be accessed at
www.zionsbancorporation.com.

Forward-Looking Statements
This press release contains forward-looking statements within the safe harbor
provisions of the Private Securities Litigation Reform Act. These statements
include statements with respect to our financial condition, results of
operations and business. The words "believes," "expects," "may," "will,"
"should," "projects," "contemplates," "anticipates," "forecasts," "intends" or
similar terminology identify forward-looking statements. These statements are
based on our beliefs as well as assumptions made using information currently
available to us. Because these statements reflect our current views concerning
future events, they involve risks, uncertainties and assumptions. Therefore,
actual results may differ significantly from the results discussed in the
forward-looking statements. The risk factors included in our reports filed
with the Securities and Exchange Commission (and available on our web site at
www.s1.com or the SEC's web site at www.sec.gov) provide examples of risks,
uncertainties and events that may cause our actual results to differ
materially from the expectations we describe in our forward-looking
statements. Except as provided by law, we undertake no obligation to update
any forward-looking statement.

SOURCE S1 Corporation

Missy Rose of S1 Enterprise, +1-704-423-2504, missy.rose@s1.com; or Jorge
Lavina of Cooper Katz & Co., Inc., +1-917-595-3047 or +1-917-386-4213,
jlavina@cooperkatz.com