Nama confirmed it had struck a deal on the Project Eagle loans with leading private investment firm Cerberus Capital Management.
Among the assets were the Lanyon Plaza and the Soloist buildings in Belfast, developed by William Ewart properties.
It is the largest single transaction by the bad bank since it was set up to clear development loans from Ireland’s main banks.
In a statement Nama said the terms of transaction are commercially sensitive and are not being disclosed but followed an extensive and competitive sales process involving bidders from Europe and the US.
Nama is understood to have paid €1.3 billion (£1.1 billion) for a package of loans linked solely to assets and development in Northern Ireland which has formed part of the Project Eagle package.
“For some time I have made clear the danger to the local economy of leaving valuable assets undeveloped and the threat that these posed to otherwise profitable businesses. I believe that this deal can be of real benefit to our economy,” he said.
Nama chairman Frank Daly and chief executive Brendan McDonagh said it was a significant achievement for the agency.
“It is Nama’s biggest single transaction to date and we are satisfied that the sales process will deliver the best possible result for the Irish taxpayer,” they said.
John W Snow, chairman of Cerberus Capital Management, said the deal will be an important foundation for its overall European strategy.
“Cerberus is a patient, long-term investor and has a well-established track record of making significant improvements to the assets that it manages,” he said.
“We believe Cerberus has the ideal base of expertise and experience to manage the Eagle portfolio and will be a strong partner for Nama, for Northern Ireland and for all the stakeholders associated with this transaction.”
Mr Robinson also said he was grateful to the authorities in the Republic for the way the deal was handled.
He said: “I would also like to put on record my appreciation to Nama and the Finance Minister in the Republic of Ireland Michael Noonan for the constructive way they have worked with the Northern Ireland Executive over the sale of this portfolio.”