General Motors has reported a net three-month loss of $15.5bn (£7.8bn) as North American sales fell by 20%.

GM took a $3.3bn charge for buying out the contracts of 19,000 hourly workers who left at the end of June.

It also wrote off $1.3bn because of reduced values of big, used cars, which cut the value of formerly leased cars owned by its financing unit, GMAC.

Without one-off charges, GM lost $6.3bn compared with a net profit of $891m in the same period of 2007.

It is the third biggest quarterly loss in the carmaker’s history.

GM shares fell 4.7% in early trading.