LONDON — A British prosecutor says five financial traders charged with rigging a key interest rate were in essence betting on a fixed horse race as their trial gets underway at Southwark Crown Court in London.

The men are accused of manipulating the Euro Interbank Offered Rate, or Euribor, a benchmark used to set interest rates on many financial products, including mortgages and credit cards. The charges were filed as part of a wider investigation into interest rate manipulation.

Former Deutsche Bank employee Achim Kraemer, 53, and former Barclays Bank traders Philippe Moryoussef, 49; Sisse Bohart, 41; Colin Bermingham, 61; and Carlo Palombo, 39, all deny the charges.

Prosecutor James Waddington says Wednesday "the only way in which these traders could make money was making sure that other people lost money."