On April 30, 2009, the German Federal Court of Justice ruled that Deutsche Börse AG, the operator of the Frankfurt Stock Exchange, cannot forbid banks to use the term “DAX” (I ZR 42/07). The abbreviation DAX (Deutscher Aktienindex) stands for the German stock market index.

The bank Commerzbank, which issues stock purchase warrants linked to the rate of the DAX, entered into a trademark license agreement with Deutsche Börse as the owner of the trademark “DAX.” After the agreement was terminated, the parties could not agree whether Commerzbank could continue to use the term DAX as a reference for its financial products.

The German Federal Court of Justice decided that Commerzbank is allowed to use the term DAX both according to trademark law and unfair competition law as a descriptive indication for its own products. The German stock market index DAX represents the most important stocks of the German financial market. By referring to the index, Commerzbank does not take unfair advantage of the repute of the trademark DAX, because the valuation of the financial products is based primarily on the evaluation of the most important German stock corporations and the developments of the stock values, as well as on the terms and conditions for each security and the creditworthiness of the bank that issues the financial products.