The Republic's attorney general has told the Commercial Court that expert statements sworn on behalf of developer Paddy McKillen are irrelevant.
Belfast-born Mr McKillen is challenging the right of the National Asset Management Agency (Nama) to take over loans made to him.
A number of economists have provided affidavits in support of his case.
However, Attorney General Paul Gallagher said they do not recognise that the property market is not liquid.
He said they are based on an incorrect premise that is not in the Nama legislation.
Mr Gallagher said most of Mr McKillen's loans are interest only and make no provision for the repayment of the capital.
He said many of them had expired and were not being repaid.
They could not be repaid on the basis of the security provided because the market was illiquid, the attorney general added.
Mr Gallagher said Noble Prize winner Dr Joseph Stiglitz - who provided a sworn statement for Mr McKillen - had based his definition of a performing loan and "systemic risk" on a basis that was not in the Nama act.
It was amazing that Dr Stiglitz had based his opinions on a basis that was not consistent with the legislation, he said.
He said it would undermine the whole basis of Nama, if it were to be suggested that the process would have to take into account the submissions of an individual borrower about the effect on his or her commercial interests.
Mr Gallagher said the legislation was trying to regulate the relationship between borrowers and bankers that had contributed to the problem and now had to be rectified at the taxpayer's expense.
"The whole purpose of the legislation would be undermined if at the end of the process you did not have a perception that the riskiest assets had been removed from the bank," he said.