General Motors CEO Edward Whitacre is ready to talk business with bidders for Saab – if they can put up the money.

General Motors took a step closer to shutting down its loss-making Swedish Saab unit Monday as CEO Edward Whitacre said that none of the bidders had submitted an offer that was good enough.

“They were not financially strong enough. It takes more money”, he told the TT news wire at the Detroit auto show.

Although saying that the managers of GM had decided to wind down the Swedish carmaker, he has not closed the door completely. If someone turns up with "a lot of money really quickly" he’s ready to sell.

“Give us 450 million dollar and we have a totally different situation”.

Last day to put forward new bids is tomorrow, Tuesday, Edward Whitacre said.

Edward Whitacre’s announcement was slammed by a Swedish union as “public negotiation tactics” and a shoddy way of putting pressure on the suitors.

“This is tasteless. GM’s timing is lousy and they behave really badly”, Anette Hellgren, head of Swedish union Unionen at Saab, told TT. “I don’t think they tell us the whole truth”

Last Friday GM decided on the liquidation of Saab and appointed restructuring group AlixPartners to supervise the orderly wind down.

"We are closing Saab," Edward Whitacre told reporters at the Detroit auto show, Dow Jones Newswire reported. "We're winding it down."

Several groups, including Dutch sportscar maker Spyker and a group comprised of Formula One boss Bernie Ecclestone and a Luxembourg investment firm, have said they presented GM with last-ditch bids to rescue Saab.

Shares in Spyker tumbled more than 10 percent in Amsterdam Monday after Edward Whitacre's statement.

"The stock has gone up because everyone was hoping the bid would go through. Now it's likely it is going down because people are losing hope," Theodoor Gilissen private banker Andre Sirks told Reuters.