Mercantile Bank Corporation Selects S1 Mobile

Seamless online banking integration and payments capabilities critical to the bank’s mobile strategy of providing value-added services to consumers and businesses

Norcross, GA – April 20, 2009 (AllPayNews) – S1 Enterprise, a division of S1 Corporation (Nasdaq: SONE) and a leading global provider of customer interaction software solutions, today announced that Mercantile Bank Corporation has selected the S1 Mobile banking and payments solution for its consumer and business customers.

Based on proven mobile technology implemented successfully worldwide since 2002, S1 Mobile is tightly integrated with S1 Online Banking and provides financial institutions with flexibility in terms of enabling them to choose between either a managed hosting or an on-premise deployment option. S1 Mobile adds to a financial institution’s multichannel offering and enables consumers and small businesses to easily access, via short message service or mobile application, their account information, transfer funds between accounts, view recent transactions, make payments, and approve transactions directly from a mobile handset. Also, S1 Mobile supports multifactor authentication and encryption to help ensure that customer accounts remain secure.

"For our financial institution, having a fully integrated mobile banking and payments solution that can serve both consumers and small businesses is critical to our vision of serving this emerging channel,” said John Schulte, senior vice president and CIO for Mercantile Bank. “The S1 Mobile solution makes it a real simple process for our customers to enroll and for us to support them. In addition, S1 Enterprise’s robust entitlements engine enables us to tailor business-specific features and the user experience to various segments of mobile users. This will allow us to continue strengthening our business banking value proposition and provide us with a strong competitive advantage.”

“Mercantile Bank’s selection of S1 Mobile continues to validate our approach of providing flexible, bank-centric solutions and payment services,” said Neil Underwood, General Manager, S1 Enterprise Americas - Retail Online. “Not only will S1 Mobile deliver seamless integration between the mobile and online banking channels, it will also establish a convenient anywhere, anytime connection to further deepen the relationship between the bank and its consumer and business customers.”

About Mercantile Bank Corporation
Based in Grand Rapids, Michigan, Mercantile Bank Corporation is the bank holding company for Mercantile Bank of Michigan. Founded in 1997 to provide banking services to businesses, individuals, and governmental units, the Bank differentiates itself on the basis of service quality and its banking staff expertise. Mercantile has nine full-service banking offices in Grand Rapids, Holland, Lansing, Ann Arbor, and Oakland County, Michigan. Mercantile Bank Corporation’s common stock is listed on the NASDAQ Global Select Market under the symbol “MBWM”.

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 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.

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.

S1 Online Banking and S1 Mobile are trademarks of S1 Corporation.

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.

Press Contacts
For S1 Enterprise
Jenni Palocsik
Sr. Product Marketing Manager
S1 Enterprise
404.923.6113 or 678.492.3141
jenni.palocsik@s1.com
or
Jorge Lavina
CooperKatz & Co., Inc.
917.595.3047 or 917.386.4213
jlavina@cooperkatz.com

Press Contacts
For Mercantile Bank of Michigan Michelle Shangraw
Retail Banking Director
Mercantile Bank of Michigan
616.726.1505
mshangraw@mercbank.com