DENIS O'Brien said he would invest in Bank of Ireland as the lender has "cleaned up its balance sheet."
"Bank of Ireland has taken the medicine," the telecoms mogul said in an interview with Bloomberg at the World Economic Forum's annual meeting in Davos, Switzerland.
While Irish banks have written down their assets to market values and been recapitalised, "other banks around Europe haven't done a mark-to-market", he added.
The billionaire also had good words to say about Ireland.
"We have taken the cod-liver oil," he said. "Ireland is definitely on the turn."
Bank of Ireland shares closed little changed in Dublin after hitting a seven-month high the previous day.
Mr O'Brien, who has a 22pc stake in Independent News & Media, resigned as deputy chairman of Bank of Ireland in September 2006.
He joined the bank's board as a director in April 2000. (Bloomberg)