New York--Investment banking kingpin Goldman Sachs & Co. invested $12 million in QSI Payments Inc., a maker of Internet-based payment software for financial companies. Goldman Sachs has warrants to invest an additional $15 million in the Sydney, Australia-based company. The move is Goldman Sachs' biggest into the sizzling e-payment infrastructure space to date, and is an attack against payment giants such as Visa International. QSI Payments, whose customers include HSBC Corp. Ltd., London, and Mastercard International, Purchase, N.Y., will use the money to expand operations in the United States, Asia and Europe. In a statement, Malcolm Turnbull, Goldman Sachs Australia and New Zealand's co-chairman, said the investment bank will use its international network to help QSI Payments.