Porsche, the German sports car manufacturer, is suing Deutsche Börse, the German exchange operator, over its exclusion from the exchange's Prime Standard because it refuses to submit quarterly reports.

The firm was thrown out of the blue chip MDAX index in August 2001 because of the firm's "fundamental policy decision" not to publish company reports. The company said it was "convinced that the practice of issuing quarterly reports is one of the causes of the stock exchanges' excessive volatility and over-reaction to news of short-term company successes".