A Belfast-born property developer begins a constitutional challenge to the work of the Republic's bad bank in Dublin's High Court this morning.
Paddy McKillen and 15 of his companies are mounting a legal challenge to Nama.
Chief among the famously secretive tycoon's objections to Nama is that it is seeking to take over his development loans in spite of his assertion that he is an unimpaired borrower.
Mr McKillen - who has already had an €80m loan with Bank of Ireland transferred into Nama - claims that the newly established agency is violating his property rights under the Constitution.
Mr McKillen, who is perhaps best known in Ireland as the developer of the Jervis Centre in Dublin, has also claimed in affidavits - submitted to the court in advance of the case - that having to deal with Nama will affect his business reputation and ability to raise funds internationally.
Defending its treatment of Mr McKillen, Nama told the High Court two weeks ago that the case presented a "very real threat" to its vital work.