Payment processing technology provider S1 Corp SONE.O urged its shareholders to reject larger rival ACI Worldwide's (ACIW.O) hostile bid to buy the company, saying the offer was not in their best interests.
"The exchange offer is subject to significant conditions that may prevent its consummation," S1 said in a statement.
S1 also raised doubts over ACI's plans to deal with antitrust and funding matters, among other things.
Last month, ACI launched a hostile bid for S1 shares, offering $6.20 in cash and 0.1064 ACI shares, per S1 share.
The offer currently values each S1 share at about $9.095, based on ACI's closing price on Tuesday.
S1's shares, which have risen about 26 percent since ACI first offered to acquire the company, closed at $8.95 on Tuesday on Nasdaq.
ACI, which makes software for financial companies, first publicly proposed to buy S1 in July in a cash and stock deal that valued S1's shares at $9.50 at the time. ACI's bid to buy S1, potentially put S1's plans to buy Israel's Fundtech FNDT.TA FNDT.O in doubt, according to analysts.
(Reporting by Brenton Cordeiro in Bangalore; Editing by Viraj Nair)