WPP media buying arm GroupM has merged two of its biggest media agencies MEC and Maxus in a plan to use cost synergies to expand its digital shop Essence.

The group plans to add traditional media capabilities and a larger geographic footprint to Essence in a move to let the company take a further role in client relations.

The merged MEC and Maxus proposition will be led by MEC Global chief executive Tim Castree.

GroupM’s portfolio will now comprise three global media agency networks – Mindshare, MediaCom, and the newly merged entity – each with more than one billion dollars in annual client revenues.

“We’re committed to improving our service to clients. These moves will give us greater focus, help us innovate, and improve our speed of delivery,” said Kelly Clark, global chief executive of GroupM.