• by Laurie Sullivan  @lauriesullivan, December 10, 2014

On the heels of this week’s big agency forecast updates, ad market tracker and aggregator eMarketer released a new interactive guide to the global ad marketplace consensus. The U.S. has fallen to less than a third of the worldwide ad market, but represents a critical mass of digital media, especially mobile.

The interactive guide, which enables users to select and view shares by year (through 2018), by market (22 countries), and by total, “digital” and mobile, indicates the U.S. has fallen to a 32.2% share of total ad spending in 2014, but represents 46.8% of mobile Internet advertising.

In total, advertisers will spend $592 billion in 2015, up 6.0% compared with the prior year. Mobile's share of worldwide digital advertising will surpass 50% in 2017, while digital's share of total advertising will reach 33% that same year. Brazil will take the No. 4 spot for the largest global advertising market by 2018, surpassing the U.K. and Germany. Indonesia will have the largest growth rate of digital advertising of any country in each year throughout the forecast. 

In 2015, eMarketer estimates that the United States, China, Japan, Germany and United Kingdom will rank as the top five markets in each advertising category. The U.K. lags Japan and Germany in total media spend, but ranks as the third-largest in digital and mobile. Japan and Germany follow as No. 4 and No. 5, respectively, for digital and mobile ad spend.

Increasing investment in North America and Asia-Pacific, and somewhat in Latin America, will offset a lagging European economy, helping to maintain growth at about 6% in each year through 2018.

The U.S. remains the dominant advertising market worldwide, spending $189 billion on ads in 2015. The total represents about 31.9% of the global ad market, higher than the aggregated total for China, Japan, Germany and the UK. The U.S. will, for the most part, maintain that market through 2018.

Mobile advertising remains a key growth driver worldwide through 2018. Advertisers will spend $64.25 billion on mobile in 2015, up 60% compared with 2014. By 2018, advertisers will spend $158.5 billion on mobile, which will account for 22% of all advertising spend worldwide, per eMarketer.

The data firm said it increased its latest figures for worldwide mobile ad investments due to faster-than-expected growth in China. Marketers will spend $6.3 billion on mobile ads in China this year, up 600% from just $913 million last year, increasing another 90% to $12.14 billion in 2015. This year, China will surpass both the U.K. and Japan to become the second-largest mobile ad market in the world.