The move follows a process that saw PHD enter final negotiations with Bang & Olufsen, only for the talks to fall through.
Initiative will handle markets including the US, with Universal McCann taking the business in the UK, Germany and Italy.
The £2 million UK account was previously handled by Carat. The business will be co-ordinated by IUM Denmark, IPG's joint-venture media agency in Copenhagen.
The bulk of the £15 milliontask will cover Europe and the US, but planning and buying in Asia is also part of the brief.
Bang & Olufsen's ad agency, the Copenhagen based Kunde & Co, is unaffected by the media appointment.
Bang & Olufsen focuses most of its UK spend on press and outdoor to support its Beovision TV range and Beocenter hi-fi collection.