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.
VW, Europe's biggest car maker, is still expected to fare better than the world's largest car maker, Toyota.
Toyota is expected to post a first-half operating loss of about 250 billion yen (£1.7bn), according to reports in Japan.