Two banks and an insurance company have accepted Microsoft's offer of technical support for Novell's Suse Enterprise Linux.

One of the three, Credit Suisse Group, does not yet use Suse Linux, a spokeswomen for the two software vendors said.

Novell and Microsoft announced a deal last month to "bridge the divide between open-source and proprietary-source software”, as Microsoft chief executive officer Steve Ballmer described it. Under the deal, Microsoft promised not to file patent lawsuits against Novell customers. It will also spend $440m on sales, marketing and licence fees in support of Novell's Suse Linux distribution, according to documents filed by Novell with the US Securities and Exchange Commission. The two companies will work together to help customers integrate their competing operating systems.

As part of its marketing support for Suse Linux, Microsoft agreed to distribute "subscription certificates”, each one entitling customers to technical support from Novell for a server running Suse Enterprise Linux. Microsoft intends to distribute around 70,000 of the certificates a year for the next five years. Customers have already activated 16,000 of the certificates in the seven weeks they have been offered, Microsoft said.

The companies declined to put a price on the certificates, but Microsoft's general manager for customer advocacy and licensing, Susan Hauser, warned: "Don't assume that we're giving them away."

Credit Suisse is a new customer for Novell, said Susan Heystee, vice president of global strategic partners at Novell, and responsible for Novell's new relationship with Microsoft. "They are making a commitment to deploying Suse Linux in their virtualisation environment," Heystee said.

Microsoft also named Deutsche Bank AG and AIG Technologies, part of insurance company American International Group, as among the customers that have activated Suse Linux subscriptions. None of the companies would say how many certificates were involved.