The chief executive of WPP, the world's largest advertising group by revenue, said most of his firm's new business in the third quarter was from clients that had left rival groups Publicis and Omnicom.
WPP, which has market capitalization of £16.4 billion ($26.2 billion), posted sales that outstripped competitors in the third quarter. Its like-for-like revenues were up 7.6 percent in the three months to the end of September.
In comparison, the U.S.'s Omnicom posted 6.5 percent growth in the quarter and France's Publicis reported growth of only 1 percent.
"Most of our new business wins have come from both Publicis and Omnicom in terms of talent – the rate of inflow into us is still running at 4-to-1. So there has been a bit of a talent outflow and a bit of a business outflow (from Omnicom and Publicis)," WPP CEO Martin Sorrell told CNBC on Friday.
Sorrell described Publicis's third-quarter performance and fourth quarter forecast as "lacking in vigor".