WPP, the world’s largest ad holding company, had the heaviest volume of deals in the quarter. Of the 12 deals announced by WPP, four were acquisitions of public relations firms, according to Ciesco’s analysis. Fellow ad holding companies Dentsu and Publicis were the next most acquisitive players in the space, each with four deals in the quarter. Of the other agency groups, Havas disclosed two deals and Interpublic announced one. Omnicom did not unveil any acquisitions during the quarter.