Ryanair (FR, Dublin International) has lost an appeal against an August 2013 UK Competition Commission (CC) ruling that it must sell most of its stake in local rival Aer Lingus (EI, Dublin International). In a brief media statement issued following the UK Competition Appeal Tribunal's (CAT) judgement, the Irish LCC said it "has instructed its lawyers to appeal this ruling to the UK Court of Appeal."

The CC had originally concluded that Ryanair's minority shareholding in Aer Lingus (29.82%) "gave it material influence over Aer Lingus and resulted in a substantial lessening of competition within the meaning of section 35 of the Enterprise Act 2002". As a result, the CC ordered Ryanair to divest itself of the majority of its holding to no more than 5%.

However, in its application to the CAT, Ryanair challenged the lawfulness of the CC's final report on six grounds, all of which were rejected by the CAT.

Among the challenges brought forward by Ryanair are that the CC did not have jurisdiction to impose requirements on the airline, an Irish company which does not carry on business in the UK. This was rejected on the grounds that Ryanair operates 11 routes to and from the United Kingdom in competition with Aer Lingus and Aer Arann Regional (Dublin International).

Aer Lingus welcomed the decision.

"Today’s CAT judgment is a key milestone on the path toward removing Ryanair from the Aer Lingus share register,” Colm Barrington, the Chairman of Aer Lingus, said.

Despite the ruling, the case is by no means over. Should the UK Court of Appeal reject Ryanair's case, the airline still has the option of the UK Supreme Court.