The announcement, made Monday, comes a week after U.S. Secretary of State Hillary Clinton met unionist and republican leaders at Stormont and hailed the power-sharing government as a positive example to other regions trying to overcome conflict.

NYSE EURONEXT chief executive, Duncan Niederauer, announced his plans in Belfast alongside First Minister Peter Robinson and Deputy First Minister Martin McGuinness.

He said the NYSE plans to create a technology service center in the city and said the skills base of the North's workforce and the personal relationship that he has struck up with Stormont leaders helped lead to the investment.

The jobs will be mainly aimed at computer science graduates and based in Belfast city center.

Invest NI, which was recently criticized in a report for failing to create enough jobs in the North, will provide up to £9.6 million to support the project.

The total of 400 jobs includes 75 which have previously been announced.

First Minister Robinson said the investment comes "at a time when global competition for such investment has never been higher."

Martin McGuinness said: "No one should doubt the scale and significance of this expansion which is a major endorsement of our local talent, knowledge and infrastructure.

"It will also send a clear message to other potential investors when such a high profile institution decides to invest here."

Northern Ireland politicians have been lobbying hard in the U.S. for more investment in recent years.

Last year, industry leaders from 80 U.S. companies attended a major conference in Belfast outlining potential investment opportunities.

In 2007, the then DUP leader and First Minister, Ian Paisley and Deputy First Minister Martin McGuinness of Sinn Féin were photographed ringing the trading bell at the NASDAQ exchange.

The pair also met Niederauer during the trip and lobbied him on making an investment in the North.

"We welcome the opportunity to partner with Invest NI and to expand our presence in Belfast. Northern Ireland will become increasingly important to our global growth strategy and complement our technology centers in Paris and London.

"Together, these centers of excellence will enable us to effectively address the growing technology and trading needs of our customers and our company," said Niederauer.

The U.S. economic envoy to Northern Ireland, Declan Kelly, also welcomed the NYSE move.

"This announcement is yet another vote of confidence in Northern Ireland by a leading U.S.-headquartered company and it is significant for many different reasons, including the number of new jobs being created," said Kelly.

"In recent weeks the world has seen very clearly that the U.S. government is strongly supportive of the compelling business case that Northern Ireland represents as a location for potential foreign investment by U.S. companies.

"Coming a week after the visit to Belfast by U.S. Secretary of State, Hillary Clinton, today's announcement serves to once again shine a light on the region as one of the best in the world for such investments because of the attractive operating environment, the competitive business case and a highly educated workforce with the strongest of work ethics.

"I would like to especially congratulate the team at Invest Northern Ireland and Minister Arlene Foster who worked very hard indeed to complete the agreement that has led to today's announcement," Kelly said.