Four South American banks have agreed to use software from S1 Corp.'s Postilion unit.

S1, of Atlanta, announced the contracts Wednesday with three Venezuelan companies — Banco Micasa, Banco Corp Banca, and Banco Banorte — and Banco Mercantil Santa Cruz in Bolivia.

Banco Micasa, a credit union that is converting to a bank, is to use the Postilion ATM management system for its 150 ATMs.

Banco Corp Banca is to use the Postilion payments platform to replace that of Banco Occidental de Descuento, which it recently acquired.

Banco Banorte is to use the Postilion merchant acquiring product to manage 10,000 point of sale terminals. Banco Mercantil Santa Cruz, Postilion's first Bolivian customer, is to use its ATM management system.

With the four new customers, Postilion has 32 customers in 11 Latin American countries.