GLOBAL: Just two companies – Google and Facebook – captured 64% of all the growth in global adspend between 2012 and 2016, according to a new study.

The latest edition of Zenith's Top Thirty Global Media Owners focused purely on media owners' revenues from advertising, excluding revenues from all other activities, in order to assess their true status in the global advertising market.

On that basis, the ROI agency found that Google (under its holding company Alphabet) is by some distance the largest media owner in the world, attracting US$79.4bn in ad revenue in 2016, three times more than the second-largest – Facebook – which attracted US$26.9bn.

The largest traditional media owner is Comcast, which took third place in Zenith's ranking, with US$12.9bn in ad revenue.

Not only have Google and Facebook bagged almost two thirds of the growth in global adspend over the past four years, the pair have also nearly doubled their share of total expenditure to 20%, from 11% in 2012.

And as internet advertising has overtaken television to become the world's largest advertising medium, so digital platforms have gained greater prominence in the media owner ranking.

As well as Alphabet (Google) and Facebook, there are five more pure-internet media owners in the top 30 – Baidu, Microsoft, Yahoo, Verizon and Twitter – and these seven together generated US$132.8bn in internet ad revenue in 2016.

That's 73% of all internet adspend, according to Zenith, and 24% of global adspend across all media.

Interestingly, Twitter emerged as the fastest-growing media owner on the list, with ad revenues surging by 734% between 2012 and 2016. The microblogging platform recently reported that ad revenues had fallen 11% in the first quarter of 2017, even as it added 9m monthly users to bring it to a total of 328m.

"The scale of the biggest platforms highlights the importance of building strong partnerships between agencies and media owners," said Vittorio Bonori, Zenith's Global Brand President.

"Brands need to deal with these platforms to communicate with consumers effectively and efficiently, and agencies need to ensure they do so on the best terms available."

Data sourced from Zenith, Guardian; additional content by WARC staff