The Commercial Court will rule today whether Seaá Quinn is allowed defend himself in proceedings against the Irish Bank Resolution Corporation (IBRC).
Mr Quinn's wife Patricia and their children claim they are not liable for loans of €2.3bn from the former Anglo Irish Bank.
In legal proceedings against IBRC, the bank, in its defence, claims fraud against the bankrupt businessman for allegedly obtaining loans for an illegal purpose.
This is denied by Seán Quinn who has been attached as a third party to the case.
He claims the bank knew the loans were for the unlawful aim of propping up Anglo's share price.
What Mr Justice Peter Kelly is to decide today is whether the businessman – as a bankrupt – is entitled to defend the allegations.