AMSTERDAM - Dutch sports car maker Spyker Cars on Monday said it has secured the financing to close its purchase of the Swedish auto brand Saab from General Motors, but still has not secured the funds for a required subsequent payment.

Spyker said it entered into a $25 million convertible loan agreement with Heerema Holding Co Inc, the holding company for a family of businesses engaged in offshore oil and gas services.

Spyker Cars Chief Executive Victor Muller, a former mergers and acquisitions lawyer, had worked for the company's Pieter Heerema operation in the 1980s and early 1990s and was involved in several acquisitions there.

The funding from Heerema, combined with money already paid, will allow Spyker to close the purchase of loss-making Saab from GM, the company said in a statement.

But Spyker also said it is still working on the financing for the final $24 million cash payment under the terms of the deal, which is due July 15, after the expected closing.

Spyker is confident that it will secure the funding for this second installment, the company said.

(Reporting by Ben Berkowitz; Editing by Bernard Orr)