The digital ad market in the United States is largely a duopoly controlled by Google and Facebook, according to recent research from eMarketer.

The report was based on an analysis of data from research firms, government agencies, media firms, and public companies, as well as interviews with top executives at publishers, ad buyers, and agencies.

The researchers estimate that 63.1% of US digital ad spend will go to Google and Facebook in 2017.

Google’s share of the US digital ad market is projected to be 42.2% this year; Facebook's share is expected to be 29.9%.

Microsoft and Verizon, the next-largest ad publishers, are each projected to receive only 4.3% of digital spend in 2017.

Google is expected to garner 33.1% of all US mobile ad revenue in 2017, while Facebook is projected to receive 26.8%:

About the research: The report was based on an analysis of data from research firms, government agencies, media firms, and public companies, as well as interviews with top executives at publishers, ad buyers, and agencies.