Six ex-traders from two banks, Barclays and Deutsche Bank have pleaded not guilt on the accusation to rig the European lending rate benchmark. Their case will be on trial in September.

The defendants consist of former Deutsche Bank trader Christian Bittar, his colleague Achim Kraemer, and four ex-Barclays Bank employees Philippe Moryoussef, Colin Bermingham, Carlo Palombo and Sisse Bohart pleaded not guity on Tuesday Feb. 7 as reported by Bloomberg. They are charged with conspiracy to manipulate the key-interest rate benchmark in European lending rate benchmark or Euribor.

Bittar was once a former star trader in Deutsche Bank and famous for bein the most profitable trader in Deutsche Bank. He and five other defendants will stand trial in September. They were accused to conspire among them and other bank officials to procure or submit false euro interbank offered rate. According to court document their conspiracy was conducted for four years, between Jan. 1, 2005 until Dec. 31, 2009.

They appeared at Southwark Crown Court in London on Feb. 7 as reported by Daily Telegraph. In their stand before Judge Nicholas Loraine-Smith, they pleaded not guilty on the conspiracy of manipulating the Euribor. In total, there are 11 traders who face similar accusation, and the six of them are the first group who stand before the judge.

All of the defendants have been taken into custody after the arrest warrants were issued by U.K. Serious Fraud Office last year. Euribor is the European counterpart of Libor in United Kingdom. They both serve as an average estimated interest rate issued by lending banks. Euribor was issued by European Money Markets Institute which took over the role from the European Banking Federation.

Prior to this case, similar cases had been on trial last year with the Libor-rigging. Watch the report regarding the charges on former traders who manipulate Libor below: