Omnicom and Interpublic Group appear to have decided that they’d be better off together as they try to stop Big Tech giants like Alphabet and Meta Platforms from eating their lunch. The longtime rivals announced on Monday that Omnicom will buy Interpublic in a stock-for-stock transaction, creating the world’s largest advertising agency. Under the terms of the deal, Omnicom shareholders will own 60.6% of the new combined company.