Volkswagen's operating profits for the first nine months of the year have fallen to 1.5 billion euros (£1.3bn) - down from 4.9bn (£4.4bn) euros in the same period last year.
The drop has been blamed on significant losses at Seat and Bentley.
Audi's nine-month operating profit fell to 1.2bn euros (£1bn) from 2.1bn (£1.9bn) after a 12 per cent drop in unit sales.
Skoda's operating profit was cut to 162m euros (£145m) from 455m (£407m) after a 19 per cent fall in sales.
Losses at Seat widened to 228 million euros (£204m) from 30 million (£27m) after sales fell 19 per cent.
Bentley swung to a 148 million euro (£132m) loss from an 83 million (£74m) profit the year before due to a big slump in sales.
"The trend in the automotive industry means that there is no reason for premature optimism. The business climate remains tough," CEO Martin Winterkorn said in a statement.
Despite this, a VW statement reaffirmed its belief that it could gain market share during the tough economic conditions.