We had a similar case in the Netherlands with Starbucks. The European Commission has the argument that if a company has a treaty with a countries tax office tha

We had a similar case in the Netherlands with Starbucks. The European Commission has the argument that if a company has a treaty with a countries tax office that results in them paying less tax than other companies without such a treaty would, then the EC regards that as a state subsidie of a company by that government. A European government is prohibited to subsidise companies in a free market (there are exemption under law), they declare this an illegal subsidie and the government must get the illegal subsidie back. As fare as I am aware, Apple is not being fined in this case, the Irish government is. Its up to the Irish government to continue this subsidy, they just will be fined again if they do. Apple seems to say here that they might withdraw from Ireland because of the uncertainties around their tax evasion strategies, not because they will actually be taxed more.