Omnicom Group, the world's largest ad holding company by revenue, will cut 4,000 jobs and shut several creative agencies, reports stated. This comes just days after it sealed its $13.5-billion takeover of rival Interpublic Group (IPG). The layoffs will target administrative roles and shrink the combined workforce to around 1 lakh, down from IPG's 51,000 and Omnicom's 75,000 pre-merger.