After twice seeing deals to sell Saab fall apart in recent months, GM's chief executive Ed Whitacre indicated ahead of Thursday's 2200 GMT (5 p.m. EST) deadline that the U.S. automaker was proceeding with the winding down of Saab as planned because no buyer had proved it could finance a purchase.
But fresh interest has emerged at the last minute, a Swedish source familiar with the matter said.
I know that Swedish parties are involved, he said, adding that a meeting of Saab board members would take place on Friday, instead of on Thursday, as originally planned.
Earlier, a Swedish newspaper said two anonymous Swedish groups were likely to submit last-minute bids proposing management buy-outs of Saab.
And separately Dutch luxury carmaker Spyker said it was preparing an improved bid.
Asked whether Spyker would bid by the deadline, Chief Executive Victor Muller said: definitely.
We are confident that we will put in an acceptable bid, Muller told Reuters.
Later on Thursday, Swedish labor union newsletter Dagens Arbete said Luxembourg-based investment firm Genii Capital had made a bid for Saab and has met with the Swedish government to let them know of its plans.
Dagens Arbete quoted a source close to Genii as saying Genii Capital is in good financial health and has strong partners.
Earlier daily newspaper Dagens Industri quoted Joran Hagglund, Sweden's state secretary for industry, as saying the bids were likely to meet today's deadline, though neither group had been able to show it had the financial backing necessary for a purchase.
We have had contacts with several different groups since the 18th of December, among them three from Sweden, Hagglund told the paper. I should think that at least two of them will submit bids to General Motors during Thursday.
The problem is that none of them can show that they have financing in place, he said, adding that Swedish sportscar maker Koenigsegg, which retracted its bid late last year, was not one of the groups.
Meanwhile Spyker had already revised an offer for the ailing Swedish carmaker several times to address GM's concerns about the source of its financing for a deal.
With hours to go before GM's offer expires analysts said bidders would be looking first and foremost to secure Saab for the value of its brand, as key engineering technology would mostly remain under the ownership of General Motors.
The actual equity in the brand is probably well beyond the value of market share of the company, said Michael Tyndall, an auto industry analyst at Nomura International. The technology belongs predominantly to GM.
Tyndall saw little chance of a reversal on GM's decision to start winding down Saab. The idea of there being an 11th hour white knight seems far-fetched to me, he said.
Spyker's Muller said last month if his offer were to succeed Saab and Spyker would operate as sister companies.
Spyker would benefit from Saab's technical resources and its distribution network, while Spyker would bring entrepreneurial skills to Saab.
The synergies are very, very clear, Muller said.
Also, the acquisition could meet the ambitions of Abu Dhabi's Mubadala Development Company, which owns about 23 percent of Spyker shares, according to a January 2008 filing with Dutch market regulator AFM, and wants to create an advanced technology industry center in Abu Dhabi.
At the same time Russia is keen to obtain Western technology to re-energize its local car industry.
Russian state-controlled Sberbank and Canada's Magna tried to buy a stake in GM's Opel unit until GM decided to keep it last year.
Russia's Vladimir Antonov holds almost 30 percent in Spyker Cars, according a recent AFM filing and has been Spyker's chairman since April 2008.
Analysts, however, remain cynical about how Spyker, which has never made a profit, is going to finance the offer.
Sweden's IF Metall union said in a statement, however, that there was every chance of a positive outcome for Saab and it expected a solid bid to materialize during the course of the day.
($1=7.816 Swedish crowns)
(Additional reporting by Reed Stevenson in Amsterdam; Editing by Erica Billingham and Greg Mahlich)