General Motors and Magna have targeted 15 July to agree on the sale of a majority stake in Opel to the Canadian parts maker and its Russian partner Sberbank, a media report said.

"There was an agreement that Magna and GM on 15 July should be far enough in their negotiations that they can reach a conclusion that serves as the basis for a contract," one person familiar with the matter told Reuters.

Neither Magna nor GM Europe would comment.

The report noted that Magna co-chief executive Siegfried Wolf said on 3 June that he expected a "final signing" in four to five weeks, after which the company would await the necessary regulatory approvals before an expected closing by the end of September.

GM Europe president Carl-Peter Forster subsequently confirmed the rough timeplan of a "definitive agreement" by July and a closing by September.

Rival bidders such as Fiat and Beijing Automotive Industry Corp (BAIC) are still hoping for a collapse in the talks in order to re-enter negotiations with GM, Reuters said.

A source familiar with the bidding process told the news agency BAIC had received approval to advance one stage further, gaining access to financial information on Opel that Fiat and Magna previously had.

GM and Magna reportedly have already largely resolved some issues such as the licensing fees Opel would pay for access to GM technology but other sticking points - such as where Opel is allowed to sell cars or who ultimately bears the risk for its EUR4b in pensions should Opel file for insolvency -- have yet to be ironed out, the report noted.