Omnicom Group's (OMC) proposed acquisition of Interpublic Group (IPG) has received an unconditional approval from the European Commission, the regulator said Monday.

The deal would, "on balance, be unlikely to raise competition concerns on any of the markets examined in the [European Economic Area]," the European Commission said.

Interpublic shares were down 2.1% in recent premarket activity, while Omnicom fell 0.4%.