Why the EU's tax probe of Apple and others is raising US ire

The European Union's crackdown on corporate tax avoidance has landed on Apple ; its antitrust regulator is demanding that the U.S. tech giant pay Ireland up to 13 billion euros ($14.5 billion) plus interest in back taxes.

The ruling is the highest profile move yet in the European battle to make international companies pay what authorities consider their fair share of EU taxes.

The EU's investigations of Apple and other multinationals trace their origins to a 2014 leak of documents that showed how big companies shop around among EU states to get as low a corporate tax rate as possible.

The revelation that has fueled popular anger in Europe, where cash-strapped governments had been raising taxes on households.

[...] the EU launched a drive to combat tax avoidance by investigating the deals that allow multinationals to slash their bills in countries like Luxembourg, Ireland and the Netherlands.

The European Commission says it's not interfering with members' rights to set their corporate tax rates, but that it should help protect countries from unfair tax competition.

Overall, Apple paid an effective tax rate of 25.5 percent on pretax income of $10.5 billion in its April-June quarter, for a total tax payment of $2.7 billion.