By Kirstin Ridley
June 17 - Britain's top fraud prosecutor is poised to bring criminal charges against former Citigroup Inc
Britain's Serious Fraud Office was expected as soon as Tuesday to charge Hayes, following the London interbank offered rate rigging scandal, which has rocked the financial industry from the United States to Japan, the source said.
It was not possible to reach Hayes on Monday and his British lawyer was not available. The SFO declined to comment.
Regulators allege Hayes and others made thousands of unlawful requests to colleagues to submit false Libor rates, colluding with other banks and at least five interdealer brokers to spread false information and influence others.
The benchmark affects hundreds of trillions of dollars worth of mortgages, credit card and other loans worldwide.
The move will also allow the SFO to stake a jurisdictional claim to a British suspect who has faced possible extradition since U.S. prosecutors charged him last year.
The SFO arrested Hayes for questioning in December. One day later, the U.S. Department of Justice lodged sealed charges of conspiracy, wire fraud and an antitrust violation against Hayes. It also charged former UBS trader Roger Darin with conspiracy.
Hayes was 27 when he joined UBS in Tokyo in 2006, becoming a senior and highly-valued trader of interest rate derivatives indexed to yen-denominated Libor. His trading generated nearly $260 million in revenues by late 2009, when he left UBS to join Citigroup after a dispute over his salary package.
But at Citigroup, he was fired less than a year later after colleagues raised concerns about inappropriate Libor requests.
Regulators have fined three banks to date over the Libor scam, with UBS agreeing a record $1.5 billion penalty to settle U.S. and UK charges.