Eight months after unveiling a unified debit processing system, MasterCard Inc. has signed a second client to use it.

The Purchase, N.Y., payments network is expected to announce today that Swiss Bankers Prepaid Services Ltd., which already uses MasterCard to process its debit payments, will upgrade to MasterCard's Integrated Processing Solutions system in the spring. The Zurich company issues MasterCard-branded prepaid cards in multiple currencies, which can be used like travelers checks.

For MasterCard, the new contract with Swiss Bankers offers an opportunity to demonstrate some of IPS' advanced capabilities, at a time when Visa Inc. is intensifying the competition for banks' processing business.

"Prepaid is a critical category for us," Laura Kelly, MasterCard's senior vice president and head of global prepaid solutions, said in an interview Wednesday. IPS "allows us to tie together a processing brand solution, in a way that allows customers to get up more rapidly and more cost-effectively than if they tried to do that from two different places."

Ms. Kelly said that by moving Swiss Bankers to IPS, MasterCard will be able to hone its processing abilities for chip-embedded cards, which are common in the European countries where the client's prepaid cards are issued. And the relationship will allow MasterCard to offer a more global demonstration of its processing capabilities. "There's a lot of very exciting things that Swiss Bankers gives us that we will not get with some of our other customers," she said.

IPS, which MasterCard introduced in April, offers a single processing system that handles signature debit, PIN debit, prepaid, and automated teller machine transactions. MasterCard already has one financial institution, Security Service Federal Credit Union in San Antonio, using its debit processing capabilities; Swiss Bankers is its first prepaid processing client.

Ms. Kelly said there are several more potential users of IPS, in the United States and abroad, but would not name them. "The IPS platform is a relatively young platform and it takes our financial institutions and partners time to evaluate their options," she said. "There's a lot going on in the economy outside."

"It's still early days, but this is a validation that you can use it outside the U.S.," said Eric Grover, the principal and founder of Intrepid Ventures, a consulting firm in Menlo Park, Calif. MasterCard still needs "to do more" with IPS, but the Swiss Bankers relationship is a "good" step, he said.