The Swiss Competition Commission said Friday it has launched an investigation into possible cartel behavior by a dozen banks including the country's two biggest institutions UBS and Credit Suisse.

The banks are suspected of colluding to influence key interest rates and the trading conditions for derivatives, the commission said in a statement Friday.

"Specifically, collusion between derivative traders might have influenced the reference rates LIBOR and TIBOR," it said.

The London Interbank Offered Rate, LIBOR, and the Tokyo Interbank Offered Rate, TIBOR, underlay many commercial interest rates.

The commission said the banks are also suspected of illegally influencing market conditions for derivatives based on these reference rates.

The foreign institutions named in the Swiss probe are Bank of Tokyo-Mitsubishi UFJ, Citigroup Inc., Deutsche Bank AG, HSBC Holdings PLC, JP Morgan Chase & Co., Mizuho Financial Group Inc., Rabobank Groep N.V., Royal Bank of Scotland Group PLC, Societe Generale SA, and Sumitomo Mitsui Banking Corporation.

Competition authorities in the United States and Britain have launched similar investigations.