The boost came on the back of strong growth in the UK, where revenues grew by 18.1 per cent over the quarter and by 11.3 per cent over the first three quarters.
This compares to a global revenue increase of 10 per cent to $2.8 billion in the third quarter. US revenue for the quarter increased by 7.8 per cent to $1.5 billion.
This brought an increase in global revenue for the first three quarters of 8.2 per cent to $8.2 billion. Net profits for the nine months to 30 September increased 9.1 per cent to $586.8 million.
Third-quarter revenues were boosted by Omnicom's customer relationship management operations, which grew by 16.7 per cent to $1 billion. Its ad business grew by a less impressive 6.5 per cent to $1.2 billion.
Omnicom also continued to make acquisitions. Third-quarter buys included Colangelo Synergy Marketing, a US sales promotion agency; the corporate events company Go! Productions; the US full-service agency Rodgers Townsend and the Indian marketing services company Gotocustomer Services.