A Japanese subsidiary of Royal Bank of Scotland has been ordered to pay a $50 million dollar fine after pleading guilty to wire fraud over its role in fixing LIBOR last year.

A Japanese subsidiary of Royal Bank of Scotland has been ordered to pay a $50 million dollar fine after pleading guilty to wire fraud over its role in fixing LIBOR last year.

RBS Securities Japan pleaded guilty to wire fraud in April last year as part of its parent's settlement with authorities in the US, the UK and Japan over LIBOR manipulation, according to court filings from the US Department of Justice.

The final approval of the fine means the bank has now paid a total of $612 million in fines to authorities across the world.

The US Justice Department said that according to the plea agreement from RBS Securities Japan, at various times from at least 2006 through 2010, certain traders tried to move LIBOR in a direction to benefit their trading positions.

LIBOR is based on the interest rates leading banks charge when loaning money to other banks overnight, which is supposed to represent the cost of a bank's lending activities.

As the primary benchmark for short-term interest rates globally, LIBOR is used as a reference rate for many interest rate contracts, mortgages, credit cards, student loans and other consumer-lending products.

Following the LIBOR scandal in 2012, Barclays, UBS and RBS have all been fined for fixing the rate in order to boost the profits of traders prior to the financial crisis.

Last month, RBS was among six companies fined a record €1.7 billion ($2.3 billion) by European authorities for colluding to fix interest rate benchmarks.

In February 2013, RBS agreed to pay $325 million to the US Commodity Futures Trading Commission, $137 million to the UK Financial Conduct Authority and $150 million to the US Justice Department.