Fermanagh businessman Sean Quinn - once believed to have been the richest man on the island of Ireland - has been declared bankrupt.
He was granted a voluntary adjudication over an alleged 2.8bn euros (£2.4bn) debt owed to Anglo Irish Bank.
Mr Quinn, 63, was stripped of control of his manufacturing and insurance business empire in April.
He and his family are engaged in a legal battle with the bank.
Mr Quinn was reputedly worth 4.72bn euros (£3.7bn) at the height of his success.
It is believed to be one of the biggest bankruptcy orders of its kind ever made in either the United Kingdom or Ireland.
Mr Quinn said he brought the application north of the border because he was born, reared and worked all his life in County Fermanagh.
But by declaring himself bankrupt in Northern Ireland it also means he only has to wait a year before going back into business - rather than 12 years in the Republic.
Irish Bank Resolution Corporation (IBRC) - the new name for Anglo Irish Bank - disputed Mr Quinn's claim that he is resident in Northern Ireland.
"The bank is examining the validity of this application for bankruptcy in light of Mr Quinn's residency and extensive business interests and liabilities within the (Irish) state," it said on Friday.
Mr Quinn claimed to have been left with no alternative but to take the "drastic decision" over problems which stemmed from "ill-fated investments in Anglo".
He accepts that he owes around 194m euros to Anglo for property loans which he cannot repay.
But the rest of the alleged debt, which relates derivative products called Contracts for Difference (CFDs) used to bet on the price of bank shares, is disputed.
The Quinn family are currently suing Anglo, claiming loans related to the CFDs were tainted with illegality.
Mr Quinn applied for voluntary bankruptcy through his lawyer and licensed insolvency practitioner, John Gordon of Napier and Sons.
Mr Gordon defended his client's decision to declare himself bankrupt in Northern Ireland as something "which he is quite entitled to do".
"Sean Quinn paid his taxes to the UK government, he has a national insurance number in the UK, all of his tax returns in the last 38 years have been in the UK, and crucially he ran his business empire from Derrylin," he said.
The order was granted during a brief hearing before a Master at the High Court in Belfast.
'Not without blame'
Following confirmation Mr Quinn said in a statement: "I have done absolutely everything in my power to avoid taking this drastic decision.
"The vast majority of debt that Anglo maintains is owed is strenuously disputed. I cannot, however, now pay those loans which are due."
He added: "Following Anglo taking control of the Quinn Group of companies, which I and a loyal team spent a lifetime building, I find myself left with no alternative."
Mr Quinn fell into financial trouble by purchasing bank shares which then became worthless.
"I am certainly not without blame. I am not in the business of pointing fingers or making excuses," he said.
"However, recent history has shown that I, like thousands of others in Ireland, incorrectly relied upon the persons who guided Anglo and who wrongfully sought to portray a 'blue chip' Irish banking stock."
Mr Quinn started his business in 1973, from the family farm in Derrylin, County Fermanagh.
He borrowed £100 to extract gravel, then started up a cement business.