The WPP shop, whose billings increased 24.8% to £271.2m, rose three places to fourth in the rankings, according to figures from Nielsen.
Grey’s top accounts were Vodafone, Procter & Gamble, GlaxoSmithKline and Volvo. It won Marks & Spencer in August and the first work will be released in April. However, it lost Vodafone to Ogilvy & Mather at the beginning of this year.
Abbott Mead Vickers BBDO remains top of the table, even though its billings fell 3.2% to £516.3m. McCann Erickson held on to second spot, as billings grew 9.2% to £390.1m.
There were two new entrants in the top ten, with Publicis UK rising four places to seventh and Saatchi & Saatchi climbing from 12th to tenth. TBWA UK and Y&R London were knocked down to 11th and 13th respectively.
WCRS had the biggest proportional fall in billings in 2016 among the top ten agencies. The Engine-owned shop fell five spots to ninth after a 23.4% drop in billings from £282.1m the previous year to £216m.
Among the top 20, Karmarama was the biggest riser, with billings up 28.7% to £119.4m.
MullenLowe London and M&C Saatchi fell out of the top 20 to 21st and 24th respectively.