Koenigsegg must inject more capital before the Swedish government is willing to back up the acquisition of GM’s loss-making Saab.

GM confirmed Tuesday that it has signed a stock purchase agreement with Koenigsegg Group AB regarding the sale of loss-making Saab Automobile AB.

However, the closing is still subject to funding agreements and the Koenigsegg Group still awaits response from the Swedish government about a state guarantee for a 600-million-euro (848-million-dollar) loan from the European Investment Bank.

The group still has many steps to take before the agreement can be concluded, Sweden's industry ministry said on Tuesday.

"The Koenigsegg Group will inject more private capital, negotiate loans with the European Investment Bank and agree with the Swedish National Debt Office on the terms for possible state loan guarantees," Jöran Hägglund, industry ministry state secretary, said in a statement.

Augie K Fabela, chairman of Koenigsegg Group, said in an interview with business daily Dagens Industri on Monday that the group is still 3 billion kronor (292 million euros, 414 million dollars) short in financing. New investors will likely come on board soon, she added.

The US auto giant signed a tentative agreement to sell Saab to Koenigsegg on June 16. Since then however commentators in Sweden have asked questions over whether the niche sports carmaker has sufficient financing to close the deal.

“Conditions to close the sale include expected funding commitments with Swedish government support and guarantees, as well as transitional assistance from GM, as Saab becomes independent”, GM Europe President Carl-Peter Forster said.