-By Steve McClellan

NEW YORK WPP's GroupM has appointed Stephen Allan worldwide chairman and CEO of MediaCom.

Allan succeeds Alexander Schmidt-Vogel, who has shifted to the new post of CEO, global trading for GroupM's worldwide operations. In that position, Schmidt-Vogel will lead buying and develop best practices for clients that purchase ads on a global basis, GroupM said.

The shop in May confirmed that Schmidt-Vogel would be relinquishing his MediaCom post.

Allan began his career at British buying shop The Media Business and, as its managing director, helped grow TMB into one of the U.K.'s largest independent media agencies before it merged with MediaCom in 1999. He also served as vice chairman of MediaCom's worldwide operation from 2003-05. After MediaCom was purchased by WPP in 2005, Allan was named CEO of GroupM U.K., responsible for managing the regional activities of MediaCom and sibling shops Mediaedge:cia and MindShare.

Irwin Gotlieb, CEO of GroupM, said in a statement that Allan "has invested his heart in the MediaCom and GroupM networks over the years. ... We are thrilled to have Steve as CEO for MediaCom globally."

Said Allan: "MediaCom is in my blood, and I am relishing the opportunity to further unlock the potential of our business. There are so many talented people inside our network and I really do believe, that for MediaCom, the best is yet to come."

The appointment is effective immediately. Allan will remain based in London. Schmidt-Vogel continues to be based in Germany.