Citi are to create more than 500 jobs in Northern Ireland.
The investment by international banking group Citi will see a major expansion of its current operation in Belfast.
The boost has been backed by a £8.4 million grant from Government business support body Invest Northern Ireland.
But it was not all good news on the local jobs front, as Bank of Ireland confirmed details of a restructuring programme that will see around 220 jobs lost at its Belfast headquarters.
The move, first announced in the summer, will see the bank centralise its business support work in Dublin.
The announcement by US-based Citi comes weeks after Northern Ireland's political leaders attended a conference in Washington hosted by Secretary of State Hillary Clinton aimed at attracting stateside business to invest in the region.
Democratic Unionist First Minister Peter Robinson and Sinn Fein Deputy First Minister Martin McGuinness welcomed the 501 new jobs as they officially opened Citi's new offices in Belfast's Titanic Quarter.
Citi, one of the world's largest banking corporations, has been in the city since 2004 and currently employs 900 staff.
The workforce service the legal, operational and technology needs of Citi offices and clients around the world, but primarily in the Europe, Middle East and Africa market.
Mr Robinson said the move would generate £16 million of new annual salaries into the local economy.
"Last month, at the US-NI economic conference in Washington, we had a unique opportunity to showcase Northern Ireland to some of the most senior people from blue chip US companies," he said.
"While we are confident that new investment will be generated as a result of the conference in the months and years to come, this latest commitment by Citi is proof positive that our ongoing efforts to secure investment are paying dividends.
"Over £8 million of Invest NI support has secured this expansion against competition from other global locations. This support will help to inject upwards of £16 million of new annual salaries into the local economy, providing the quality, world class employment opportunities that local people so richly deserve."
Mr McGuinness added: "At a time when global businesses are still trying to manage their way out of the downturn, Citi has recognised that this region offers the skills, infrastructure and support necessary to develop its presence here and support growth in key global markets.
"Over the next five years, Citi plans to create 440 new high quality roles in its technology and operations divisions and a further 61 new specialist posts in its legal and compliance division. This is an extremely significant boost for the local economy, particularly in terms of job numbers and the high quality of the positions."
Bill Mills from Citi said Northern Ireland had proved itself a great place to set up.
"As a global company with a presence in more than 120 countries, we continually evaluate the best locations for expansion to ensure maximum productivity and growth," he said.
"Northern Ireland has repeatedly exceeded our expectations since our initial investment in 2004."
Enterprise Minister Arlene Foster added: "Citi is one of the most prestigious financial services companies in the world, so this major investment, one of the largest in recent months, is a real endorsement of the NI investment proposition.
"I hope that following this announcement and the economic conference in Washington that other investors are encouraged to look more closely at Northern Ireland as an investment location."
US economic envoy to Northern Ireland Declan Kelly, who was instrumental in organising the investment conference, hailed the move by Citi.
"Today's announcement is another landmark moment for Northern Ireland which underlines once again that the region is one of the most attractive in the world for inward investment at the present time," he said.
"I am particularly pleased that today's announcement involves Citi and a great representative in Bill Mills, the company's leader in the Europe, Middle East and Africa (EMEA) region, because they have been huge supporters of Northern Ireland and also the US government's economic mission in the region.
"Only a few weeks ago at the US-NI economic conference in Washington, which I had the pleasure of organising on behalf of Secretary Clinton, Bill played a very prominent role as an advocate for Northern Ireland, including chairing a special round-table discussion on financial services.
"Bill and his company's leadership is demonstrated by the additional commitment which is being announced today and we all look forward to working further with him and his colleagues in the months ahead."
The latest jobs boost brings to 750 the number of US posts created in Northern Ireland in the wake of the investment conference.
The Dow Chemical Company and the Terex Corporation are among the companies creating work.
Mr Kelly added: "I look forward to building on this momentum by continuing to work with Minister Foster and Invest NI to showcase Northern Ireland across the United States, and I am optimistic that in the coming months we will see even further positive news for the region."