The Law Firm of Levi & Korsinsky, LLP Notifies Shareholders of Claims of Breaches of Fiduciary Duty by the Board of S1 Corporation in Connection With Merger With ACI Worldwide Inc.

NEW YORK, NY--(Marketwire - Aug 1, 2011) - Levi & Korsinsky notifies investors of S1 Corporation ("S1" or the "Company") (NASDAQ: SONE) of claims of breaches of fiduciary duty and other violations of state law against the Board of Directors of the Company in connection with a merger proposal from ACI Worldwide Inc. (NASDAQ: ACIW). Under the terms of the transaction, ACI Worldwide will pay S1 shareholders $9.50 in cash or ACIW stock per share of S1 stock they own. The transaction would have a total approximate value of $540 million. A complaint was filed in Delaware state court.

Click here to learn how to join the action: http://www.zlk.com/s-one-sone, or call: 877-363-5972.

On June 27, 2011, S1 entered into a definitive agreement to merge with Fundtech Ltd. Under the terms of that agreement, Fundtech shareholders will receive 2.72 shares of S1 common stock for each Fundtech ordinary share they own. The merger is expected to close in the fourth quarter of 2011.

The claims concern whether the S1 Board of Directors have taken the necessary steps to maximize shareholder value and whether the ACI Worldwide offer of $9.50 per share adequately compensates S1 shareholders. On August 1, 2011, the Company reported that total revenue in the second quarter of 2011 increased 22% to $63.3 million from $51.8 million in the second quarter of 2010 and total revenue in the six months ended June 30, 2011 increased 18% to $121.2 million from $102.9 million in the six months ended June 30, 2010.

If you own common stock in S1 and wish to obtain additional information, please contact Joseph Levi, Esq. either via email at jlevi@zlk.com or by telephone at (212) 363-7500, toll-free: (877) 363-5972, or visit http://www.zlk.com.

Levi & Korsinsky is a national firm with offices in New York, California and Washington D.C. The firm has extensive expertise in prosecuting investor securities litigation involving financial fraud and represents investors throughout the nation, concentrating its practice in securities and shareholder litigation. Attorney advertising. Prior results do not guarantee similar outcomes.