The European Union authorities on Thursday opened a formal investigation into whether Luxembourg granted McDonald's overly generous tax breaks.
The move is the latest sign that Margrethe Vestager, the bloc's competition commissioner, is determined to widen a crackdown on corporate tax avoidance that has already ensnared three companies with operations in Luxembourg, a tiny European Union member state that has grown rich on financial services during recent decades.
Ms. Vestager said she was examining whether Luxembourg's authorities had deviated from their national tax law and from a tax treaty between Luxembourg and the United States.
