Amazon’s US digital ad revenues will grow 53% in 2019, as it continues to steal share from the Facebook-Google duopoly. That will amount to $3.92 billion in incremental US ad revenues this year, or 82% of Amazon’s worldwide total. And nearly half (43.9%) will come from mobile ad spending.

Less than one-fifth of Amazon’s incremental revenues ($900 million) will come from outside the US.

In the US, there doesn’t seem to be a dominant Amazon ad product attracting marketers. According to an ad-buying survey conducted by Cowen and Company in December 2018, ad-spend allocation among US senior ad buyers’ clients is dispersed almost evenly across five categories: traditional display ads, product display ads, sponsored products, video ads and headline search.

However, when combining these ad products into larger categories, the search-type ads make up the majority of allocation (57%) over the combined traditional display and video ads, which make up only 43% of ad spend on Amazon.

But a few factors, such as the expansion of video ads, could affect these proportions in the near future. Amazon has reportedly been testing video ads that appear within mobile search results.

This development could bolster both facets of the company’s ad business. We expect that more than $36 billion will be spent on video ads in the US this year, with more than 35% going to Facebook and YouTube. But the introduction of more video ads—an in-demand ad format that Amazon has lacked for years—could give the company a chance to siphon share from the duopoly.

It will also help Amazon accelerate its already fast-growing mobile ad business. We expect the company’s total mobile ad revenues to grow 74.9% in 2019, making up 40% of its total digital ad revenues.