The European Commission said yesterday it has extended the scope of its in-depth investigation into whether the new Gibraltar corporate tax regime selectively favours certain categories of companies, in breach of EU state aid rules.

The Commission will now also examine the Gibraltar tax rulings practice, introduced by the new Gibraltar income tax act, which allows companies to ask for advance confirmation of whether certain income is subject to tax.

The EU executive has assessed 165 tax rulings granted by the Gibraltar tax authorities to different companies in 2011, 2012 and up to August 2013, saying it has concerns that potentially all assessed rulings may contain state aid.

The Commission said it had doubts whether the way in which Gibraltar tax authorities applied the new income tax act was compatible with EU state aid rules.