A German regional court has opened the door to an investor law suit against credit rating agency Standard & Poor's over its assessment of Lehman Brothers securities before the collapse of the U.S. investment bank.

The Frankfurt higher regional court rejected a lower court ruling that had found the court had no jurisdiction.

The case will be sent back to the lower Frankfurt court for action and a decision, a spokeswoman for the higher regional court said on Monday.

The German court has jurisdiction because S&P has assets in Germany and the person bringing the suit is a German resident, the higher regional court said in a statement.

German law firm KWAG brought the suit on behalf of an investor who had bought 30,000 euros ($40,000) worth of Lehman securities based on a favorable S&P rating, a spokesman for KWAG said. The ruling could open the door to further suits, he said.

Lehman Brothers collapsed in September 2008.

An S&P spokeswoman declined comment. ($1 = 0.7536 euros)

(Reporting by Jonathan Gould; Editing by Andrew Callus)