When you think of website retail, the first name that probably comes to mind is Amazon.com, Inc. (NASDAQ:AMZN) -- and with good reason. According to Deloitte's 2017 Global Powers of Retailing Report, the e-commerce giant is the largest e-retailer in the world. Another company that likely comes to mind is discount leader Wal-Mart Stores, Inc. (NYSE:WMT), which takes the spot as top retailer and sits fourth in e-commerce as it battles to expand its online sales in a market dominated by Amazon.

While these two retail juggernauts catch most of the headlines, there are others quietly working to increase their online sales. E-commerce represented an estimated $322 billion in 2016, and that figure is expected to climb to $485 billion over the next five years, according to Statista.com.

With that much up for grabs, it is not surprising that any number of companies would be vying for their share. eMarketer recently released data for the top e-commerce retailers in the U.S. While Amazon and Wal-Mart take some of the top spots, you may be surprised to know that other members of the old guard of retail are high on the list. 

Best Buy store front sign.

Best Buy heavily invested in e-commerce. Image source: Best Buy.

Best Buy 

Best Buy Co., Inc. (NYSE:BBY) was one of the first retailers to feel the pinch from the phenomenon of "showrooming" -- the practice of viewing items in a brick and mortar retail store, then buying those items later from an online retailer, often at a reduced price. The company fought back against this practice by investing heavily in its e-commerce business, which increased 17.5% and represented 15.6% of its domestic revenue in its most recent quarter. For the full year, the company increased online sales by 21%.

Best Buy reported that a full 40% of orders placed online were picked up at its stores. This resulted in increased foot traffic and higher conversion rates.

Hands holding mobile phone using The Home Depot app.

The Home Depot looks to e-commerce to drive growth. Image source: The Home Depot.

Home Depot

The Home Depot, Inc. (NYSE:HD) is a staple in the home improvement arena. It hosts more than 2,200 locations in North America, though it hasn't opened any new stores in the last three years and has increasingly focused on e-commerce to drive future growth.

Over the last year, its e-commerce sales amounted to 5.9% of revenue, and the company has grown online sales by 19%. It might seem counterintuitive that a home-improvement retailer would rely on online customers to grow sales. By focusing on an interconnected retail strategy, Home Depot has been able to increase its sales per square foot by 5.5%, and it is notable that more than 45% of online orders are picked up at a store. 

Macy's Herald Square Flagship Store.

Macy's sees double digit online sales growth. Image source: Macy's.

Macy's 

Macy's, Inc. (NYSE:M) is known for its flagship Macy's and Bloomingdale's stores. The company has struggled with lower same-store sales, which were down 4% in the most recent quarter and 2.9% for the year.

The company has also been working to close 100 stores, with 66 already closed and 44 more to go. The good news amid all the doom and gloom is that the company's online sales continued to exhibit double-digit growth. While Macy's didn't break it out in the most recent earnings release, eMarketer reports that Macy's e-commerce grew 12.5% and represented 17.9% of its total revenue over the last year. The company continues to tweak its mobile app and website to further accommodate and increase online sales.

Danny Vena owns shares of Amazon. Danny Vena has the following options: short June 2017 $72.5 calls on Wal-Mart Stores, long January 2018 $57.5 calls on Wal-Mart Stores, long January 2018 $55 calls on Wal-Mart Stores, and short June 2017 $72.5 calls on Wal-Mart Stores. The Motley Fool owns shares of and recommends Amazon. The Motley Fool recommends Home Depot. The Motley Fool has a disclosure policy.