A Japanese investment banking unit of Royal Bank of Scotland Group Plc was ordered on Monday to pay a $50 million criminal fine after pleading guilty to wire fraud over its role in manipulating the benchmark interest rate LIBOR.

RBS Securities Japan Ltd had entered its plea last April 12, as part of its parent’s $612 million settlement to resolve criminal and civil probes by authorities in the United States, the United Kingdom and Japan into rate manipulation.

LIBOR is also known as the London Interbank Offered Rate. It is a benchmark for rates on trillions of dollars of mortgages, credit cards, student loans, derivatives contracts and other financial instruments.

In a Dec. 31 joint court filing with the U.S. government, RBS Securities Japan said that from at least 2006 to 2010, some of its traders sought to move LIBOR in a direction that benefited their trading positions. Authorities said this enabled the traders to profit at the expense of counterparties.

The filing said probes revealed wrongful conduct related to LIBOR submissions for Japanese yen and another currency that involved about 20 RBS traders, including four at RBS Securities Japan. That unit said it “accepts responsibility” for its employees’ misconduct.

“Today’s sentencing of RBS is an important reminder of the significant consequences facing banks that deliberately manipulate financial benchmark rates,” Mythili Raman, acting head of the U.S. Department of Justice’s criminal division, said in a statement.

The Justice Department said the $50 million fine and plea were approved by U.S. District Judge Michael Shea in Hartford, Connecticut. RBS has offices in Stamford, Connecticut.

More than a dozen banks and brokerage firms have been probed worldwide over alleged LIBOR manipulation. Barclays Plc , ICAP Plc and UBS AG have also reached settlements with U.S. authorities.

The case is U.S. v. RBS Securities Japan Ltd, U.S. District Court, District of Connecticut, No. 13-cr-00073.