Check out our latest stock picks for long-term investors.

Trying to pick growth stocks to buy and hold for the next five years, 10 years, or even longer can be a challenge. The key is finding companies that have a proven business model, a track record of success under a stellar management team, and catalysts that should help propel the business -- and stock -- forward for years to come. Here are five top long-term stocks to buy now for buy-and-hold investors. 

An hourglass of money

Image source: Getty Images.

Company Market Cap P/E (TTM)  Forward P/E
Under Armour
(NYSE:UA)(NYSE:UAA)
$11.8 billion 56 37 
Shopify
(NYSE:SHOP)
$3.8 billion (106) (857)

Baidu
(NASDAQ:BIDU)

$57 billion 12 29
Take-Two Interactive
(NASDAQ:TTWO)
$4.3 billion 2,594  19
Walt Disney Co.
(NYSE:DIS)
$165.8 billion 18 15

P/E = price-to-earnings ratio. TTM = trailing 12 months. Data source: Yahoo! Finance, as of Jan. 1, 2017. 

Under Armour

Under Armour stock dropped more than 25% in 2016. The market punished the company after third-quarter earnings in October when -- even though the company posted solid revenue and earnings growth -- management noted that they would continue to invest heavily in new growth, which meant that previously set earnings estimates would not be met as quickly as anticipated. While Wall Street sent shares diving, management exhibited the kind of long-term mindset that makes Under Armour such an attractive buy-and-hold stock, one that now looks to be selling at a discount compared with where shares were trading a few months ago.

Under Armour has grown revenue to around $5 billion annually in 2016, more than double what it was two years ago, and expects that figure to grow to $7.5 billion by the end of 2018. The tailwinds that could send sales far past that $7.5 billion in the years ahead are a growing athletic-apparel market worldwide, Under Armour's taking market share away from current industry leaders, a growing footwear segment that is expected to be up more than 50% year over year in 2016, and a few major projects like the company's overhauling its manufacturing processes.

Shopify

Shopify stock looks expensive because the company isn't yet profitable, but that's because it is still plowing its available money into new growth, including $286 million that the company raised in August 2016 in another stock offering. The investments seem to be paying off, as Shopify's sales rose 89% in the most recent quarter year over year. The e-commerce platform has increased customer count 62% over Q3 2015 to 325,000 merchants, including some big-name partners that are increasing Shopify's market appeal. The total value of sales processed through Shopify's platform was almost $4 billion during the quarter, twice as much as a year ago. 

Shopify is increasing its customer reach and ease of use with its newly launched merchant mobile app, upgrades for Apple Pay and payments through Facebook Messenger, and other growth initiatives that could make 2017 an even higher growth year than 2016. Over the longer term, Shopify is laser-focused on becoming the go-to payments portal for a growing market of online merchants, which makes it look like an opportunity for huge growth in the years ahead. 

Baidu

Baidu is the Chinese search engine company that, like its main U.S. counterpart that itself exited China in 2010, provides an array of other services, from email to digital maps, as well as undertakes moonshot projects like autonomous vehicles and artificial intelligence. Baidu has gained from China's remarkable rise in internet users, and could continue to gain for years to come as the population there continues to become connected to the internet at a rapid pace. There are already nearly twice as many internet users in China -- 721 million -- as the entire U.S. population. However, the internet penetration rate is still low at just 52%. Even a 10% higher penetration rate in the country would mean about 138 million new potential customers for Baidu. 

Baidu's share price has risen over 1,200% in the last 10 years, but in 2016 actually dropped 13%, partially because of a small decrease in online advertising revenue due to new government regulations and Baidu's committing to weeding out bad advertisers. That small drop could be a chance to buy in for what could be very long-term growth as Baidu leads this important and growing market, and now trades for just 12 times earnings. One big growth driver, other than the vastly growing market of internet users in China, is Baidu's online media streaming service iQiyi, which has over half a billion monthly users and is reportedly considering an IPO. 

Take-Two Interactive

Take-Two Interactive was one of the top performing stocks within the gaming market in 2016. Take-Two is likely to keep its momentum going in 2017 and the years ahead as it produces popular new content, such as Grand Theft Auto and NBA 2K17, and increases its focus on driving digital and mobile growth. Take-Two's sales rose 21% in the most recent quarter, year over year, but earnings actually declined. Still, similar to Shopify, Take-Two looks like a company that is plowing money into renewed growth, but shows solid long-term potential for huge gains. Low earnings are to blame for the company's absurdly high P/E ratio over the trailing 12 months, but Take-Two's current price is just 19 times next year's forecast earnings.   

Disney

Disney had spent much of 2016 out of favor with Wall Street after late 2015 earnings showed its cable segment, particularly its ESPN network, under pressure from cord-cutters who don't want to pay expensive cable packages, which led to declining subscriber rates. While its cable segment does make up nearly half of total revenue, and ESPN is a big chunk of that, the short-term concerns seem overblown and continue to leave the buying window into this great company open for long-term-minded investors. 

Disney stock had momentum at the end of 2016, with shares gaining 15% in November and December, but with valuation remaining at a reasonable level. The company looks like a long-term winner as it continues to find ways to deliver its cable network properties to consumers in new ways, such as through Apple TV and other streaming services, as well as through their own growth online and on mobile. Outside of cable, the company is firing on all cylinders when it comes to developing its theme park operations, continually pumping out extremely well-performing movies, and increasing its brands and characters in consumer products.

Seth McNew owns shares of Apple, Under Armour (A Shares), Under Armour (C Shares), and Walt Disney. The Motley Fool owns shares of and recommends Apple, Baidu, Facebook, Shopify, Take-Two Interactive, Under Armour (A Shares), Under Armour (C Shares), and Walt Disney. The Motley Fool has the following options: long January 2018 $90 calls on Apple and short January 2018 $95 calls on Apple. The Motley Fool has a disclosure policy.