Young, 44, and Williams, 49, from Nottingham, were remanded in custody for sentencing on 7 May, despite attempts by their lawyers to continue with bail.
The 22-day trial in the Island's Royal Court brought to an end a complex four-year investigation involving fraud squad officers, lawyers, forensic accountants, over 1 million prosecution documents and pre-trial costs running into seven figures.
Young lost $10m (pounds 6m) of investors' money in currency deals effected through UBS's Jersey subsidiary, Cantrade Private Bank, which has pleaded guilty to four charges of criminal recklessness by making misleading statements. The bank will also be sentenced on 7 May.
Williams, a former tax adviser and partner with Touche Ross's Nottingham branch, produced documents purporting to audit Young's false trading figures which at one point claimed profits of $16m (pounds 10m).
Investors flew in from around the world, including Canada, the US and Australia, to tell how they had been persuaded to part with their money by Young's documents claiming an impressive track record in currency dealing.
The court heard that he and his wife Maureen, a fellow trader, made $2m in commission plus a further $3.8m from a secret commission-sharing deal with Cantrade.
Lawyers and fraud squad officers were delighted with the result, which they believe sends out a clear message that Jersey is capable of mounting a major and complex fraud trial. This should be a timely message for the Home Office, which is currently reviewing the Island's financial laws and regulations.Reuse content