Amazon.com (AMZN 1.30%) is growing at a rapid clip. In its fourth quarter, the e-commerce giant's revenue climbed 22% year over year. Even more, the company's total 2016 sales increased 27%, hitting an impressive $136 billion. But can Amazon keep up its steep growth over the long haul? 

Based on the trajectory of global e-commerce sales, Amazon is still barely tapping into a fast-growing trend. In 2016, Amazon's $136 billion of revenue only represented a small fraction of global online retail sales. In 2016, e-commerce sales worldwide hit $1.9 trillion, up from about $1.5 trillion in 2015.

Chart showing Amazon revenue and global e-commerce sales.

Data for Amazon is from Morningstar. E-commerce sales estimates are by eMarketer. Chart source: Author.

But wait! This massive addressable market for Amazon can't continue skyrocketing now that it's already nearing $2 trillion annually, right? Well, according to eMarketer, annual global e-commerce sales will more double over the next four years, to about $4.1 trillion.

Of course, Amazon isn't the only company vying for this enormous market opportunity. Even Wal-Mart has recently stepped up its investments in the space with its acquisition of e-commerce company Jet.com. And essentially every major retailer on the planet wants to improve their e-commerce offerings. But as the world leader in online retail, Amazon looks perfectly positioned to benefit. 

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