Britain's Serious Fraud Office says a senior executive from a U.K. bank has pleaded guilty to conspiracy to defraud in a case of market-rigging.

It is the first criminal conviction in the country's investigation into a global scheme to fix the London Interbank Offered Rate, also known as LIBOR, an interest rate that affects trillions of dollars in loans and mortgages worldwide.

Other countries, including the U.S., are also investigating the case.

Britain's Serious Fraud Office said Tuesday it has charged another 11 individuals who await trial and is still investigating others. It did not name the banker who pleaded guilty, in line with court orders.