Rick Sirvaitis, President and CEO of GM Mediaworks - established to handle General Motors' $3.5 billion media-buying account - has been pushed out by parent Interpublic Group after losing GM's business last week, reports AdAge. GM awarded the business to Publicis Groupe's GM Planworks, which has handled media-planning for GM. Mediaworks staffers are expected to be hired by Publicis, moved within Interpublic or laid off.