Just how big is Amazon in the e-commerce space? Very big. According to estimates by eMarketer, Amazon is expected to capture 49.1 percent of the e-commerce market in the U.S. this year. This is an increase from a 43.5 percent share of this market in 2017, according to eMarketer’s estimates.

Amazon’s e-commerce sales place the retailer as the clear leader in eMarketer’s ranking of the leading online retailers in the U.S., far ahead of No. 2 eBay, which has a 6.6 percent market share this year, according to the eMarketer estimates.

Amazon also controls almost 5 percent of the total U.S. retail market (online and offline), according to eMarketer.
The consulting firm’s forecast for Amazon is that this year the company will generate $258.2 billion in U.S. retail e-commerce sales, an increase of 29.2 percent compared with the year-ago total. Amazon’s “Marketplace” sales will represent an “increasingly dominant portion of its ecommerce business – 68.0 percent this year, compared with 32 percent for Amazon direct sales,” according to eMarketer. “By the end of 2018, sales generated from Amazon’s Marketplace will be more than double that of Amazon’s direct sales in the U.S.”

The computer / consumer electronics category ranks as the leading product segment for Amazon, with estimated U.S. sales of $65.8 billion this year, according to eMarketer. This would represent more than one-quarter of Amazon’s retail e-commerce business. Apparel and accessories surpassed books and music in 2017 to become the second-largest category on Amazon at 15.4 percent of overall company sales, according to eMarketer.

The eMarketer report cited food and beverage and health, personal care and beauty as the online retailer’s other fast-growing categories. Food and beverage will grow more than 40 percent this year, while health and beauty will show a sales increase of almost 38 percent, according to the eMarketer report. Both categories represent “just a small portion of Amazon’s U.S. retail e-commerce sales,” eMarketer noted.