The December edition of the ROI agency's Advertising Expenditure Forecasts calculated that internet advertising will account for 94% of the growth in adspend between 2017 and 2020.
And the greater part of this, it said, will be captured by Google and Facebook, plus the Chinese platforms Baidu, Alibaba and Tencent.
Between them these five platforms increased their share of global internet adspend from 61% to 72% between 2014 and 2016, and captured 83% of the growth in internet adspend over that time, a trend which will continue.
The US and China alone will contribute 47% of new ad dollars between 2017 and 2020, Zenith predicted; adding in Japan, the UK and Germany means the top five countries will contribute 57% of growth.
Zenith went on to consider city-level spending and concluded that, between 2016 and 2019, adspend in the ten biggest-contributing cities will grow by a total of US$7.5bn, representing 11% of growth over these years.
“We are seeing a battle played out in business, marketing and media between big players and small players,” said Vittorio Bonori, Zenith’s Global Brand President.
“Growth is coming from big countries and big cities, and being captured by big platforms.”
Separate data from MAGNA outlined a broadly similar trend in respect of digital advertising, with digital media sales predicted to reach 44% of total ad sales in 2018 and 50% by 2020.
“The transition to a digital-centric media world accelerates as digital ad sales continue to grow as fast – and often faster – than expected,” said Vincent Létang, EVP, Global Market Intelligence at MAGNA.
“Meanwhile linear television struggles in most major markets (US, UK, Australia etc.) as CPM inflation is no longer strong enough to compensate for declining ratings and lower demand from consumer goods.”
Sourced from Zenith, MAGNA; additional content by WARC staff