Mobile advertising spend is growing six times faster than desktop globally, according to ZenithOptimedia.

Mobile ad spend – including classified, search and display ads, across apps and the mobile web on both smartphones and tablets – is forecast to increase at a CAGR of 38.3 per cent between 2014 and 2017. By comparison, desktop has a predicted CAGR of 6.7 per cent.

In 2014, ZenithOptimedia estimates that mobile spend will reach $25.8bn (£16.5bn) – five per cent of total advertising expenditure – rising to $68.2bn by 2017 – 11.3 per cent of total spend.

Mobile is expected to far over-index on this market share when it comes to new ad dollars, accounting for 51 per cent of extra spend between 2014 and 2017 – an extra $42.4m – compared to 25 per cent, or $20.6bn, from desktop.

Showing the strong links between mobile and social, Facebook and Twitter will together account for 33 per cent of all mobile ad spend in 2014 – compared to 10 per cent share of digital overall.