Carat’s latest worldwide advertising expenditure forecasts for 2015 and 2016 predicts global advertising spend to grow by 4% in 2015 to US$529bn — a slight decline from the 4.6% growth predicted in March — and by 4.7% in 2016. UK growth is predicted to be 6.4% in 2015 and 5.5% in 2016.

The increase is fuelled by digital media spend, which Carat predicts will, in 2016, account for more than a quarter of total advertising spend. This strong growth is in turn fuelled by online video, programmatic and mobile. According to Carat’s predictions, US programmatic transactions will account for 52% of non-search digital advertising spend by the end of 2015, with a growth rate of around 20% a year predicted to continue for the next few years.

Overall, mobile is experiencing the greatest spend growth across all media: Carat predicts a year-on-year increase in mobile spend of 51.2% in 2015.