The tech industry duopoly of Facebook and Google have long eaten up the lion's share of the digital advertising market, leaving other companies, online news outlets, and the rest of the internet to fight over the scraps in search of viable digital monetization strategies.

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The tech giants' domination of the digital ad space isn't likely to change anytime soon, but another even bigger fish is in third place and slowly eating into Facebook and Google's respective market shares. Acccording to a report from eMarketer, Amazon's billion-dollar ad business is growing at a rate of 50 percent per year. The report found that the e-commerce powerhouse's share of US digital advertising revenue is slated to rise from 6.8 percent in 2018 to 8.8 percent in 2019.

The eMarketer report projects that total digital ad spending in the US will grow 19 percent to $129.34 billion this year, which accounts for over half of estimated total US ad spending. Mobile advertising makes up an increasingly large chunk of that, estimated at more than $87 billion this year.

The overall revenue figure encompasses digital ads appearing on all digital devices: desktops and laptops, smartphones and tablets, and ad revenue from all platforms owned by each company, meaning YouTube ad spending counting toward Google's market share and Instagram's counting toward Facebook.

While Amazon has gained in market share, Google actually lost a hair off its still substantial lead, dropping from 38.2 percent in 2018 to an estimated 37.2 percent in 2019. Facebook is in a distant second, projected to grow marginally from 21.8 percent in 2018 to 22.1 percent of the digital ad market in 2019.

Amazon's growth also looks to be affecting the tech companies that are in fourth and fifth places. Microsoft's digital-ad market share (including LinkedIn) is set to drop from 4.1 percent in 2018 to 3.8 percent in 2019, according to eMarketer, while Verizon (which owns AOL and Yahoo) is set to drop from 3.4 percent to 2.9 percent.

For those keeping track, those 2019 market share numbers add up to a little over 25 percent of the digital advertising market left for everyone else.

This article originally appeared on PCMag.com.