The European Commission (EC) has opened an in-depth investigation to assess the proposed takeover of parts of RWE unit Innogy by rival German utility E.ON under the EU Merger Regulation, citing concerns that the deal could reduce competition in gas and power retail markets of four member states.

The announcement of an EU probe little more than a week after the EC had given the green light to RWE’s takeover of the renewables operations of both E.ON