Apple will be expanding its campus in Hollyhill, Co.Cork, Ireland and is adding a new building that will provide new office space and room for 1,000 additional employees by mid-2017. With the move, Apple is trying to boost its presence in the country where it declares much of its overseas profit for tax purposes.

"Apple will always be proud to call Ireland home," Chief Executive Officer Tim Cook said in a speech at Trinity College in Dublin.

Apple has had a presence in Ireland since 1980, when the company opened its first facility in Cork. It is estimated that the company supports nearly 18,000 jobs across the country, including over 5,000 direct Apple employees - an increase of 25% in the past year alone.

Apple has also announced that it is partnering with the Sustainable Energy Authority of Ireland to support research in offshore energy technology and is establishing a 1M euros Ocean Energy Industry Fund. This will support new ways of capturing wave energy and converting it to renewable electricity in support of their global commitment to powering all facilities with renewable energy.

European antitrust officials are probing Apple's tax dealings in Ireland, with Irish Finance Minister Michael Noonan saying a ruling will probably be made after Christmas.

Apple has said in the past it doesn’t use "tax gimmicks," and the Irish government has indicated that it’ll fight an adverse decision in the European Union Court of Justice.

The European Commission has already ordered Dutch authorities to recover up to 30 million euros from U.S. coffee chain Starbucks and Luxembourg to do the same with Fiat Chrysler for their tax deals.

Rulings on Apple and Amazon's tax arrangement with Luxembourg authorities are still pending.

Apple paid an average tax rate of just 2.5 percent on around $109 billion of non-U.S. profits in the five years to 2014, a fraction of Ireland's 12.5 percent tax rate.