The former head of Anglo Irish Bank David Drumm has been found guilty of conspiracy to defraud and false accounting charges.
The jury at Dublin Circuit Criminal Court took 10 hours to reach their verdict on day 86 of the trial.
Drumm worked with the bank's former finance director Willie McAteer, John Bowe of the treasury department and former Irish Life and Permanent (IL&P) chief exec Denis Casey to defraud investors.
A payment of £1bn was sent from Anglo to IL&P and back via Irish Life insurance until payments added up to €7.2bn.
The prosecution argued that Drumm did this to make the bank's balance sheet look better than it actually was to deliberately induce people to invest in Anglo even when he knew it was in trouble.
But Drumm's lawyers said the transactions were not dishonest, and were a perfectly legitimate way to manage a balance sheet.
Drumm led the bank between 2005 and 2008, before Anglo Irish was nationalised in 2009 and then wound down in 2011.
He moved to the US in 2009, but was extradited in 2016 to face trial for the fraud charges.