Omnicom’s results revealed organic growth of 3.5% in the second quarter of 2017, while overall revenue totalled $3.79bn, representing a fall of 2.4% compared with the same period last year. 

Overall revenue in North America was down 6.6% for Q2 2017, and down 3.1% for the year to date. UK revenue was down 3.7% for the second quarter, and down 5.9% for the first half of 2017. 

Meanwhile revenue in the Asia Pacific region lifted 1.3% overall for the second quarter, but organic growth was up 7.1%. Year-to-date figures showed growth of 3.4% for the region. 

Rival ad-holding company Publicis Groupe’s results showed a 0.8% increase in organic growth, with revenue amounting to $2.9bn. 

According to John Wren, Omnicom’s CEO, its US business was brought down by its PR unit, shopper marketing and branding businesses. 

"We’re unhappy with it, have forensically identified it and are taking actions to do something about it," Wren said.