NEW YORK (AdAge.com) -- Along with being the world's largest advertising holding company, WPP Group has built itself into the fourth largest business research company -- trailing only Thomson-Reuters, Bloomberg and Nielsen. One area of market data in which CEO Martin Sorrell has taken a particular interest is that regarding cost cutting by large marketers around the globe. He warned the recent Ad-Tech conference in New York about the long-term results of today's draconian cuts in marketing service budgets.