Porsche's chairman Wolfgang Porsche and board member Ferdinand Piech are being sued over its failed takeover bid for Volkswagen.
Seven hedge funds are seeking 1.8bn euros (£1.5bn) in compensation.
Porsche has been accused of misleading markets in the run-up to its takeover bid for VW in 2008. It initially dismissed speculation it was seeking to takeover VW, but later revealed that it owned or had positions on almost 74% of VW shares.
Some investors had bet against Volkswagen shares, expecting them to fall in the absence on any firm takeover bid from Porsche, but Porsche's disclosure of an increased holding triggered a stock market squeeze on VW shares as investors rushed to buy them to cover their short positions.
Porsche, which has earlier faced similar cases, has denied any wrongdoing.