US billionaire Wilbur Ross, who made a €500m profit buying shares in Bank of Ireland at the height of the financial crisis, has ruled out investing in Permanent TSB Group Holdings.

Permanent TSB was the only Irish lender to fail European stress tests last month.

"Having gone to the dance with Bank of Ireland, and we had a very good waltz with them, I think we’ll be faithful to it," Ross said in an interview with Bloomberg Television in London today.

He was responding to a question about whether he will consider investing in Permanent TSB. 

Ross was part of a group of five investors to help rescue Bank of Ireland in 2011 by buying a 35% stake for €1.1 billion. 

He sold his shares this year, making a €500m profit, according to data compiled from company filings Bloomberg stated. 

Permanent TSB this month began to court investors as it seeks to fill a capital hole that emerged during European Central Bank stress tests. 

The bank's chief executive Jeremy Masding said last week the lender may need to raise as much as €150m of capital as a result of the ECB assessment.

He said the 99.2% state-owned bank has covered more than 80% of an €855m shortfall that emerged in the extreme scenario of the tests with the help of €400m of state-owned contingent convertible bonds and by shrinking its balance sheet.