A Chicago equity firm will buy Fundtech for $388 million, apparently putting an end to the global payments technology provider’s merger agreement with S1 Corp.

Fundtech, an Israeli company with U.S. headquarters in Jersey City, N.J., will have to pay a $12 million breakup fee to S1, according to their earlier agreement.

Atlanta-based S1, an online banking and payments provider, said it has five days to consider making a counter proposal and is “currently reviewing its options.”

ACI Worldwide of Elkhorn, Neb., had launched its own hostile takeover bid for S1, raising its stake to an estimated $540 million.

Clal Industries, controlling shareholder of Fundtech, said it has accepted the offer from GTCR Fund in Chicago, which said it would merge that operation with its BankServ property and keep it based in Jersey City. BankServ had earlier acquired NetDeposit from Zions Bancorp.

S1 is an Atlanta-based provider of online banking and payments software with more than 3,000 clients worldwide. It also is owner of PM Systems Corp., a South Carolina-based provider of online banking and security services to about 175 credit unions.

Fundtech is an Israeli company with U.S. operations based in Jersey City, N.J., and said it has a client list of more than 1,000 companies worldwide using its wire transfers, ACH origination, cross-border payments and remittance. Fundtech said it also operates the world’s largest SWIFT service bureau.

S1 is a provider of online banking and payments software to more than 3,000 clients worldwide. It also is owner of PM Systems Corp., a South Carolina-based provider of online banking and security services to about 175 credit unions.

Fundtech said it has a client list of more than 1,000 companies worldwide using its wire transfers, ACH origination, cross-border payments and remittance. Fundtech said it also operates the world’s largest SWIFT service bureau.