Sean Quinn Jnr has denied having any documents that would show what happened to the rents or profits of two Russian companies that he actively managed.
The son of bankrupt businessman Sean Quinn Snr is being cross examined by lawyers for IBRC.
The most famous of the Quinn's Russian property assets is the Kutuzoff tower in Moscow with a rent roll valued last year at €15m.
This jewel in the crown, as it has been described, was operated by Quinn company Finannstroy and Sean Quinn Jnr used to be its general director.
He was also actively involved in another company, Logistica, but has denied knowing anything about the accounts which were in Russian or about what happened to the rents in either firm.
Asked by Mr Justice Peter Kelly as to how he could have managed assets if bamboozled by these Russian documents he replied that he managed tenant issues indirectly through the Russian employees.
Sean Quinn Jnr is the last member of his family to be cross examined by IBRC, which is trying to find out whether they have fully disclosed all relevant information relating to their bank accounts and assets which are the subject of freezing orders.