The European Commission has ruled that Ireland has illegally aided Apple with a favourable tax arrangement between 2003 and 2014. Apple has now been ordered to pay back 13 billion euros plus interest.

Through Ireland’s special arrangement, the Commission argues, Apple was given an unfair advantage over other businesses. The new ruling is part of a three-year campaign against corporate tax avoidance. Apple has, predictably, announced it will appeal the decision. And Ireland, while it would be the recipient of the 13 billion, has vowed to appeal as well.

Read more about Apple’s tax situation here.