The regional court in Braunschweig dismissed two of the claims which together sought just under €5 million.
Those suing argued that Porsche manipulated the stock market with its stunning 2008 announcement that it was taking over Volkswagen, which in turn sent Volkswagen stock prices through the roof.
The takeover eventually failed, leading to massive losses for investors.
Judge Stefan Puhle said the press releases issued by Porsche on March 3 and 10, 2008 were, “in their contents not grossly false.”
A spokesman for Porsche said the court's decision on Wednesday was a 'positive signal.'
It became apparent that the claim would likely be rejected at a hearing back in June. Puhle said then that it would be a "difficult act" to convict Porsche and made it clear that the German Supreme Court (BGH) had created extremely high barriers to such judgements.
Three further claims which seek a combined total of €4.1 billion, are still pending at the regional court.
The luxury car maker was later saved by Volkswagen, which completed its takeover of Porsche last month.