British prosecutors have filed criminal fraud charges against former UBS and Citigroup trader Tom Hayes for allegedly trying to manipulate benchmark interest rates, in the first effort by British authorities to seek criminal penalties against someone they allege was involved in manipulation of the London interbank offered rate, or Libor.

The UK's Serious Fraud Office in a statement said Hayes has been charged with eight counts "of conspiracy to defraud in connection with the investigation by the Serious Fraud Office into the manipulation of Libor."