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Top 10 US Ecommerce Companies in 2018

Amazon’s Marketplace Sets the Pace for Sales Growth

About This Report
Amazon will claim nearly half of US retail ecommerce sales in 2018. Sales will be driven by Amazon’s marketplace, which will account for 68.0% of business.
Table of Contents

Amazon dominates the ecommerce market in the US. This year, retail ecommerce sales are expected to reach $525.69 billion, with Amazon claiming nearly half of that total—up from 38.3% in 2016. The remaining top 10 ecommerce companies, ranked by digital sales, will account for 21.7% of the market in 2018.

The success of Amazon Marketplace, where third-party sellers can sell new or used products alongside Amazon offerings, is a key factor in the ecommerce giant’s growth. We forecast Amazon’s marketplace will account for 68.0% of Amazon sales and 33.4% of total US retail ecommerce.

Sales on competitor marketplaces trail Amazon, as they attract a lower number of sellers (and in some cases the same sellers). According to a May 2018 survey from Amazon intelligence company Feedvisor, for example, 52% of US Amazon sellers also used eBay’s marketplace. The overlap in the number of sellers on Walmart and was much lower, at 17% and 8%, respectively.

We estimate that No. 2-ranked eBay will lose market share for the second straight year, falling from 7.1% to 6.6%. The scale of Amazon’s marketplace means it’ll capture at least 30% of ecommerce sales across each major product category (except auto and parts).


Corey McNair


Andrea Szasz
Forecasting Analyst
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