Advertising Martin Sorrell quits as head of world's biggest ad group WPP Updated : April 15, 2018 09:34 PM IST Sorrell, who built WPP into the world’s biggest advertising agency through 33 years of dealmaking, quit after an allegation of personal misconduct. The company will consider internal and external candidates for the top job in a process that could take several months. Analysts have speculated that the sprawling group, which was being restructured after a year of lower spending from some clients, could now sell off some assets if led by different management. Subscribe to Moneycontrol PRO at just Rs.33/- per month for the first year. Use code SUPERPRO. Limited period offer. Available on Web and Android.