Parker Green - the Newry-based property and investment company - has refinanced its loans held by the Cerberus investment fund.
The Co Down firm - headed by Dr Gerard O'Hare - is the first to re-finance with the US-based private equity firm since it first took over control of the loans in 2014, as part of its £1bn purchase of Nama's Northern Ireland loan book.
It will now develop planned expansions on properties on both sides of the border, including Newry's Quays Shopping Centre, which the firm claims will add £50m to its portfolio upon its completion.
Dr O'Hare said: "This is a red letter day, not just for everyone in Parker Green but also for the economy in both Northern Ireland and the Republic.
"It's a sign of emerging confidence in the investment potential that has been stunted since the recession and the frustrations of having to operate under the Nama experiment."
The re-financing was backed by New York-based Garrison Investment Group LP and its joint venture partners Earlsfort Capital in Dublin. The deal will also allow Parker Green to complete extensions to the Fairgreen Shopping Centre in Carlow and to its buildings on Merrion Street in Dublin.
Dr O'Hare added: "The past number of years working with Nama have been difficult and in reality we needed the injection of a commercial player like Cerberus into the market to bring their reputation and expertise to the table. Ultimately its business that best understands business.
Cerberus spokesman Chip Smith said: "Cerberus has been working closely with key stakeholders in government and business in Northern Ireland over the last nine months following our successful bid for Project Eagle portfolio in April 2014.
"This is the first of many deals for Northern Ireland and we welcome the commitment by Parker Green to secure this agreement."