> ASI's 2014 structure was an adaptation of a Double Irish scheme, an Irish IP–based BEPS tool used by many US multinationals. Apple did not follow the traditional Double Irish structure of using two separate Irish companies. Instead, Apple used two separate "branches" inside one single company, namely ASI.[34] It is this "branch structure" the EU Commission alleged was illegal State aid, as it was not offered to other multinationals in Ireland, which had used the traditional "two separate companies" version of the Double Irish BEPS tool. Under the Double Irish structure, one Irish subsidiary (IRL1) is an Irish registered company selling products to non–US locations from Ireland. The other Irish subsidiary (IRL2) is "registered" in Ireland, but "managed and controlled" from a tax haven such as Bermuda. The Irish tax code considers IRL2 a Bermuda company (used the "managed and controlled" test), but the US tax code considers IRL2 an Irish company (uses the registration test). Neither taxes it. Apple's subsidiary, ASI, behaved like it was IRL2, it was "managed and controlled" via ASI Board meetings in Bermuda, so Irish Revenue did not tax it. But ASI also did all the functions of IRL1, making circa €110.8 billion[6] of profits from non–US sales. The EU Commission contest IRL1's actions made ASI Irish, and the functions of IRL1 over-rode the Bermuda Board meetings in deciding the "managed and controlled" test. The commission had not brought any cases against US multinationals using the standard double two separate companies Irish BEPS tool. (https://en.wikipedia.org/wiki/Apple%27s_EU_tax_dispute)
In other words if they had actually set up two separate Irish companies instead of just using two separate branches of a single Irish company, their tax scheme would have been fully legal and not considered state aid. (Since many other companies availed themselves of such a scheme.)