A jury acquitted six former brokers of fraudulently trying to manipulate a widely used benchmark interest rate, dealing a major blow to a years-long international investigation.

The jury on Wednesday reached unanimous verdicts to acquit five of the brokers - former Icap brokers Colin Goodman and Danny Wilkinson, former RP Martin brokers Terry Farr and James Gilmour, and former Tullett Prebon broker Noel Cryan - on all counts. The sixth broker, Icap's Darrell Read, was acquitted on one count of conspiring to defraud, but the jury is still deliberating on another count against him.