Stocks are up over 15% in the last year, and those short-term returns trounce what an investor might have expected to earn from other asset classes like bonds and real estate. But the real eye-popping growth numbers in the stock market come in multiples of years -- or decades. That's the time frame that better allows a company's competitive advantage to shine through and compound.

With that ultra long term in mind, Motley Fool contributors today are turning the spotlight on a few stocks that they see as having particularly promising outlooks. Read on to see why Wayfair (NYSE:W), Splunk (NASDAQ:SPLK), and JD.com (NASDAQ:JD) all deserve a spot on your watchlist.  

Log on to growth

Demitri Kalogeropoulos (Wayfair): The home goods retailing market has a much smaller online penetration than other consumer categories like electronics and apparel. The niche poses difficult shipping challenges, after all, that make it tough to deliver consistently high customer service.

A man enters his credit card information online.

Image source: Getty Images.

Wayfair is making strides at meeting those challenges, in part by building out its own shipping infrastructure. And it is reaping the rewards in terms of significant market share growth. Sales have expanded by almost 50% in each of the last three quarters, accelerating to a 49% boost in the second quarter of 2018.

The company isn't profitable today, and investors can expect management to continue prioritizing sales gains as Wayfair expands deeper into international markets. But that's not the same as saying any rival can achieve what Wayfair has. Overstock tried to slow its growth through price cuts and increased marketing spending this year before quickly realizing that the challenge wasn't working.

That's another piece of evidence suggesting Wayfair is building a durable business as its number of active buyers approaches 13 million and repeat orders climb to 66% of all volume. Metrics like these point to continued market-thumping gains for the company as the home goods market shifts more toward online sales in the years to come.

A best bet on big data

Nicholas Rossolillo (Splunk): As the world goes digital and more devices get hooked up to the internet every year, Splunk's industry-leading big data parsing software only gets more lucrative. The company was founded in 2003, but the value of its software-as-a-service business has really found its groove in the last few years as enterprises try to make sense of the information their websites, digital systems, and devices create.

Since the company went public in the spring of 2012, revenue has gone from about $100 million a year to $1.27 billion in 2017. The next big push is for $2 billion in annual revenue by 2020, and management expects to start turning an adjusted operating profit for the first time later this year. As a result of all that growth, the stock has nearly doubled twice since its debut. 

A server room.

Image source: Getty Images.

The best could be yet to come for Splunk, though. The business is still relatively small, carrying a market cap of only $15 billion. However, that's big enough that Splunk has gotten hungry and went on an acquisition streak over the last year -- scooping up smaller technology outfits to boost its own abilities in artificial intelligence and increase its efficacy in the fight against cyber crime. Plus, as high expenses to push all-out growth slowly begin to pare back, the bottom line could grow in dramatic fashion in the years ahead. 

With big data only getting bigger (the amount of digital information is supposed to grow by double digits for the indefinite future), Splunk looks like a stock for the long haul.

The real e-commerce platform leader

Rich Duprey (JD.com): The difference between JD.com and Chinese e-commerce rival Alibaba is that the latter is actually more like eBay than Amazon.com. It's a platform for third-party sellers, rather than selling stuff itself.

JD.com, on the other hand, is a true online retailer and its sales grew 31% in the second quarter and it's forecasting them to grow 25% to 30% this year, though that came in below expectations of 31% annual growth. But the e-tailer is going up against tough comparable sales numbers from the year-ago period and it just came off big promotional events in June and July.

While it is true that Alibaba sucks a lot of the oxygen out of the room as it is estimated to control some 58% of all e-commerce in China, JD.com with a $47 billion market cap and $18.5 billion in quarterly sales is no shrinking violet. Further, even if its growth has eased up some, it's still posting phenomenal rates, and it has some important backing, including Walmart, Google, and Tencent.

Its stock is down 36% from its 52-week high, marking a new low for the e-tailer, and it is trading at just a fraction of its sales. Although betting on an industry's 800-pound gorilla is often a smart strategy, going with the second banana in this case, and particularly because its price has been knocked about, makes JD.com a good investment that can be held onto for decades.

John Mackey, CEO of Whole Foods Market, an Amazon subsidiary, is a member of The Motley Fool's board of directors. Suzanne Frey, an executive at Alphabet, is a member of The Motley Fool's board of directors. Demitrios Kalogeropoulos owns shares of Amazon and JD.com. Nicholas Rossolillo owns shares of Alibaba Group Holding Ltd., Alphabet (A shares), Alphabet (C shares), and Tencent Holdings. Rich Duprey has no position in any of the stocks mentioned. The Motley Fool owns shares of and recommends Alphabet (A shares), Alphabet (C shares), Amazon, JD.com, and Tencent Holdings. The Motley Fool recommends eBay. The Motley Fool has a disclosure policy.