A sign points to Opel headquarters in Ruesselsheim, central Germany. A number of suitors have stepped up with bids for stakes in the carmaker. (Michael Probst/Associated Press)

The co-CEO of Canadian auto parts maker Magna International said Tuesday he is confident a deal to take over GM unit Adam Opel GmbH will be complete by the middle of July.

Siegfried Wolf, who is co-chief executive of the company with Bill Walker, said Magna "wants to come to an agreement by July 15."

"We want to make Opel into a company that stands along with its partners and distributors for success, growth and innovation," Wolf said.

Magna and Russian firm OAO Sberbank signed a non-binding agreement last month, which envisages Sberbank taking a 35 per cent stake and Magna a 20 per cent stake in the General Motors Corp. subsidiary.

GM would retain a 35 per cent interest in Opel and Opel employees would hold 10 per cent.

The deal was touted in Russia as a major coup for the country's troubled auto industry — based on signals that Magna would produce Opel cars in Russia.

MI Developments Inc., a spinoff of Magna International that is controlled by the two companies' Austrian-born founder Frank Stronach, said last week that it's in discussions about building three new plants in Russia.

But the German government has said this week it is still talking with other bidders, despite the negotiations with Magna.

Italian automaker Fiat, which has expanded its North American presence by acquiring 20 per cent of Chrysler, has said it hasn't given up on getting Opel.