Achilleas Kallakis and Alexander Williams, both 44 and from London, tried to swindle Allied Irish Banks (AIB) out of £740 million and Bank of Scotland (BOS), as it was known, of £22m between August 2003 and November 2008.
The jury was told Kallakis used the proceeds of his fraud to fund the lifestyle of the super-rich with a fleet of chauffeur-driven Bentleys, a private plane, a private helicopter, a luxury yacht moored in Monaco harbour and a collection of high-value artworks.
The pair were convicted at Southwark Crown Court of two counts of conspiring to defraud the banks after a four-month trial. They will be sentenced today.
The men used forged documents as part of their plot to use AIB money to buy properties and BOS cash to convert an former passenger ferry into a super yacht, the court heard. The loss to AIB was more than £56m and £4.8m to BOS.
The duo, who both used various aliases, operated from London business premises in Mayfair, where Kallakis masqueraded as a legitimate property tycoon and Williams a financial consultant.
The pair defrauded AIB by using the forged or false documents to obtain substantial loans to finance the purchase of what was mostly a commercial property portfolio.