By Margot Patrick and David Enrich 

LONDON--British prosecutors filed criminal charges Monday against three former bank traders for alleged fraud, opening a new front in a global investigation into alleged rigging of benchmark interest rates, with more charges in the pipeline.

The U.K.'s Serious Fraud Office said it is charging three former Barclays PLC traders with "conspiracy to defraud" for their alleged roles rigging the London interbank offered rate, or Libor. The agency, which opened its criminal investigation in July 2012, also is likely to file charges against three former ICAP PLC brokers for allegedly helping bank traders manipulate rates, according to people familiar with the case.

Monday's charges bring to 13 the number of individuals criminally charged in the U.S. or U.K. investigations into Libor, a benchmark used to set interest rates on trillions of dollars of loans and other financial contracts.

The SFO's latest charges represent a broadening of the Libor investigation, which got under way in 2008. They serve as a reminder of the scandal's scope and the pervasive nature of the alleged misconduct, even as the Libor investigation begins to be overshadowed by nascent criminal and civil examinations into potential manipulation of other financial benchmarks.

Until now, criminal charges filed against individuals in the U.S. and U.K. have all been in connection with an alleged rate-manipulation ring led by a single trader: Tom Hayes, who used to work in Tokyo for UBS AG and Citigroup Inc. and who has pleaded not guilty to U.K. charges.

But the charges against the former Barclays employees-- Peter Johnson, Jonathan Mathew and Stylianos Contogoulas--don't appear to relate to that investigation. Most of their alleged activity took place during a different time period, and Barclays wasn't part of Mr. Hayes's alleged ring, according to people familiar with the U.S. and U.K. investigations. A lawyer for Mr. Mathew declined to comment. Lawyers for Messrs. Johnson and Contogoulas didn't respond to requests for comment.

Other alleged rings remain under scrutiny. Authorities in the U.S., U.K. and European Union have been investigating a group of former traders from several banks for allegedly working together to manipulate the euro interbank offered rate, or Euribor, according to people familiar with that case.

The likely U.K. criminal charges against the former ICAP brokers-- Colin Goodman, Darrell Read and Daniel Wilkinson--are notable in part because the U.S. Justice Department last September charged the men with similar fraud-related offenses. They haven't entered pleas to the U.S. charges.

"We would not be surprised to find that he would be charged," said Matthew Frankland, a London lawyer representing Mr. Wilkinson.

After the U.S. filed charges, lawyers for the former ICAP brokers were in the unusual position of pushing the SFO to file criminal charges against their clients, according to people familiar with the case. The reason: Being charged in the U.K. likely would preclude the men from being extradited to the U.S. to face similar charges, these people said. The former brokers would prefer to be tried in Britain because the penalties they would face if convicted are much lighter than in the U.S.

Relations between the Justice Department and the SFO soured in late 2012 over a similar incident. U.S. officials informed their British counterparts at the time that they planned to file criminal charges against Mr. Hayes. Within days, the SFO arrested Mr. Hayes, a move that the Justice Department perceived as impeding the U.S. from nabbing a prime suspect, these people say. The dispute was escalated to senior officials on both sides of the Atlantic.

People close to the SFO said the agency has been in close contact with the Justice Department about its decisions about whom to charge and that the two agencies have patched up their relationships since the 2012 fracas.

The flurry of announced and anticipated charges by the SFO comes as the agency tries to regain momentum in its Libor case. People involved in the investigation say it was nearly derailed last year when Mr. Hayes, who had been cooperating with the agency, changed his mind and decided to fight the charges against him. The SFO had been counting on Mr. Hayes to testify against his alleged co-conspirators, and without his help it became much harder to bring charges against other individuals, these people said.

The former ICAP brokers allegedly worked with Mr. Hayes and other bank traders to rig rates, according to the Justice Department. ICAP, which serves as a middleman for large institutions looking to buy and sell financial products, last September settled the U.S. and British Libor investigations, agreeing to pay $87 million. Its chief executive at the time apologized for the firm's misconduct.

Barclays was the first bank to resolve its case, paying about $450 million in June 2012 and admitting wrongdoing. A political furor over the settlement led to the abrupt resignations of Barclays' chairman, chief executive and chief operating officer.

Write to Margot Patrick at margot.patrick@wsj.com and David Enrich at david.enrich@wsj.com

Subscribe to WSJ: http://online.wsj.com?mod=djnwires

ICAP (LSE:IAP)
Historical Stock Chart
From Mar 2024 to Apr 2024 Click Here for more ICAP Charts.
ICAP (LSE:IAP)
Historical Stock Chart
From Apr 2023 to Apr 2024 Click Here for more ICAP Charts.