The European Union on Tuesday set out its case against Apple's sweetheart tax deals with Ireland, saying it believed they breached its rules on receiving state aid and gave the US tech giant an unfair advantage.

Brussels released a letter which the EU's Competition Commissioner, Joaquin Almunia, sent to the Irish government in June formally giving its reasons for opening an investigation into Dublin's arrangements with Apple.

It said the Irish government's treatment of Apple "appears to constitute state aid and therefore breaches the 28-member EU's rules on a free internal market."

It asked Ireland to provide further information about the deals, which have benefitted Apple since 1991.

If found at fault, however, Apple would be required to repay potentially billions in restitution.

Uncertain outcome

An independent US Senate investigation into Apple's tax affairs in 2013 found that the company had used Irish-registered businesses, which were not tax-resident in any nation, to shelter billions of dollars in profit from authorities.

Prior to the EU watchdog's publication on Tuesday, some tax lawyers said they had their misgivings about whether the EU executive could force Apple to repay money in tax savings if it found the money saved by the company to be unfair state aid.

The lawyers said a more likely scenario would be that Ireland and Luxembourg could be pressed to change their light-touch approach to taxing multinational firms.

Apple said Monday it was not aware of having received any selective treatment from Irish officials.

hg/cjc (dpa, AFP)