One of the golden circle of businessmen lent money by Anglo Irish Bank to buy shares in the rogue lender has been ordered to help a fraud investigation.
Gerald Conlan will be forced to come forward with documents and information on how Anglo arranged the deal in an attempt to prop up its stock market value.
Others in the so-called "Anglo 10" secret investment engine were the co-owner of the K Club, Gerry Gannon, and developer Joe O'Reilly, who was behind the Dundrum Shopping Centre.
Mr Conlan, who has previously refused to co-operate with the inquiry, has agreed to make himself available.
The Director of Corporate Enforcement Paul Appleby applied in Naas District Court to force the businessman into helping investigators, three years on from the deal.
"The orders granted ... require Mr Gerald Conlan to produce certain documents and information related to Anglo Irish Bank's provision of a substantial loan to him for the purchase of its shares in July 2008," the watchdog said.
"Mr Conlon is a witness who had earlier declined to make himself available to the ODCE in its investigations of possible company law offences by Anglo and its officers.
"However at today's hearing, it was indicated on behalf of Mr Conlan that he would be complying with any court order made.
"I welcome the successful utilisation of these new Criminal Justice Act provisions in aid of the Anglo investigations."
It is the first time the Criminal Justice Act has been used to force a witness to assist investigations since they became law in August.
Anglo lent the group of investors, described as long-standing clients, €451m in July 2008 to buy 10% of the bank.
The deal was lined up to prevent the stake acquired by businessman Sean Quinn through complex and secret share trades known as contracts for difference (CFDs) from coming to the market.
There were major concerns a sudden flooding of trading floors with the Quinn stake would see Anglo's stock market value plummet.