None of them have been charged and some have yet to be interviewed. Southwark crown court was told about the SFO contact at a hearing attended by Tom Hayes, a former trader at investment banks Citigroup and UBS. Hayes is the first person to be charged with manipulation of the benchmark rate.
Hayes's appearance was the latest stage in the process relating to the eight charges he faces for allegedly rigging Libor.
Wearing a pale blue v-neck sweater, 34-year-old Hayes sat in the dock in a packed courtroom alongside two former traders at money brokers RP Martin, Terry Farr and James Gilmour.
None of the three entered a plea and they were given a further 28 days to plead guilty or not guilty. The Hayes trial is not likely to begin until 2015. The three defendants were granted legal aid.
The court heard that a draft of the indictments against the three had named 22 other individuals as potentially being investigated for Libor rigging. The judge said their naming does not necessarily mean they are guilty of wrongdoing.
But the identities of these individuals were not revealed in court after the judge heard representations they had not been formally charged or investigated. Their names were removed from the indictments.
The judge lifted an injunction that had been placed on the Wall Street Journal over the naming of eight of the individuals.
Hayes, the first person to be charged over Libor-related offences, spoke only to confirm his identity. He is charged with variously conspiring with Royal Bank of Scotland, JP Morgan Chase, Deutsche Bank, Rabobank, RP Martin, HSBC and Tullett Prebon.
The charges relate to periods between August 2006 and December 2009, when Hayes worked for UBS Securities Japan; and December 2009 and September 2010, when he worked for Citigroup Global Markets Japan.
The charges allege that Hayes conspired to manipulate yen interbank offered rates. A charge relating to "other, unspecified, interbank offered rates" has been removed.
Gilmour has been charged with one count of conspiracy to defraud, between August 2006 and December 2009, and Farr faces two counts covering the same alleged offence.
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