Tom Hayes, a former trader from the UBS Group AG and Citigroup, Inc., was sentenced to 14 years in prison by the London court, according to a report from Bloomberg.
Hayes, who last worked for UBS, was found guilty of rigging the benchmark London interbank offered rate (Libor) rates to benefit his trading positions.
The sentence of 14 years in prison is among the longest to be given for a financial crime in the U.K.
Jeremy Cooke, the judge who presided in the case, said that a "message needs to be sent to the world of banking," according to Bloomberg.
"Probity and honesty are essential, as is trust. The Libor activities of which you took part in, put that in jeopardy," he said.
Before the punishment was handed out, Prosecutor Mukul Chuwala said that rigging the Libor "erodes public confidence and undermines the integrity of financial markets," according to Bloomberg.
"Hayes played a leading role," he said.
Hayes was alleged to have set up a network of brokers and traders from 10 different financial institutions by Britain's Serious Fraud Office (SFO), according to a report from Reuters.
Reuters adds that he cajoled or bribed them to help rig the Libor, a crucial benchmark for around $450 trillion of financial contracts and consumer loans, from 2006 to 2010.
The outcome of Hayes' trial, the first for a defendant accused of Libor rigging, is significant for the SFO, Stephen Ross, partner and head of the financial disputes team at London law firm Collyer Bristow, said according to Reuters.
"This is a success for the Serious Fraud Office, which has put immense resources into pursuing this ground-breaking prosecution, seen as a test case to determine whether it can prosecute other allegedly dishonest Libor traders," he said.
Bloomberg reports that Hayes' defense of the accusations was that the manipulation was widespread in the industry.
Neil Hawes, Hayes' lawyer, told Cooke that Hayes activities have been happening for at least five years prior to his joining UBS. He added that there were "others above him who were aware of the activity."
Bloomberg adds that UBS said in a statement that the case is "between the SFO and Mr. Hayes."
"The bank has resolved this legacy matter with most authorities," the company said in the statement.
