Earlier this month, GM said it would start winding down the company while still looking for a buyer, but it said on Tuesday that this process would be suspended immediately, "pending the close of the transaction".
"General Motors, Spyker Cars, and the Swedish government worked very hard and creatively for a deal that would secure a sustainable future for this unique and iconic brand," John Smith, GM vice president, said in a statement.
Despite years of haemorrhaging money, the 60-year-old Swedish group has many fans, some of whom believe it could be profitable with the right owner.
"It's a really brilliant brand. It's probably one of the biggest brand mismanagement stories in the history of the automotive industry," Tim Urquhart, analyst at IHS Global Insight, said.
"Saab could have been the Swedish Audi if it had been taken on in the right way 20 years ago.
"It's been completely mismanaged, underinvested in by people who don't understand what the brand means, and what it has the potential to mean."
However, many analysts have questioned whether Spyker is the right owner.
Spyker, which only produces several dozen handmade sports cars a year, hopes to benefit from Saab's technical resources and distribution network.
For its part, Saab will get funds to survive and an injection of entrepreneurial spirit.
The market sensed a deal was in the offing on Monday, bidding up Spyker shares as much as 80 per cent before they eased on Tuesday, and then were halted in Amsterdam trading.