According to data from e-commerce research firm Internet Retailer, Amazon remains miles ahead of the U.S. competition in the online retail space. In 2013, Amazon's online retail sales amounted to $67.9 billion, more than the next 9 largest e-retailers combined.
Surprisingly, the second largest player in the e-commerce game is not a large retailer such as Wal-Mart or Staples, but Apple. The iPhone-maker reportedly sold goods and services worth $18.3 billion through its website, the App Store and the iTunes Store in the past year.
Amazon's increasingly dominant position in the e-commerce market is owed largely to the company's aggressive growth strategy. Under CEO Jeff Bezos, Amazon has become known to reinvest most of its earnings, which is why the company has yet to turn a meaningful profit.
Correction: A previous version of this post said that these are the largest online retailers in the world. While that is definitely true in Amazon's case, the chart below only includes U.S. companies, hence these are the largest U.S. online retailers.