The Atlantic Philanthropies organisation founded by Chuck Feeney has confirmed it will "complete" its three decades of grantmaking around the world by 2016.
The organisation has been working towards this date since 2009, when it set out its timeline plan for an end of operations.
It was founded as a philanthropic outlet for the reclusive billionaire owner and to operate for around a 30-year time span.
In that time, it has granted over $6bn worldwide, with €1.25bn going to projects in the Republic of Ireland and Northern Ireland.
It has worked with educational institutions, health and elder care. It has also campaigned for equals rights across the globe.
In a statement on its website Atlantic Philanthropies said: "As many of you know, we will complete grantmaking by the end of 2016.
"After that, we will make final payments, monitor ongoing grants and evaluate and share our experiences to enhance our grantees' work.
"Atlantic will complete its grantmaking in areas where work remains to be done, but we hope our support will have achieved and continue to contribute to measurable and lasting progress.
"We aim to do this while also minimising disruption to those grantees that may have been reliant on our financial support."
As well as Ireland, it has operated in Australia, Bermuda, South Africa, the US and Vietnam.