Investing in high-growth stocks is a great way to beat the broader market's returns by a wide margin. But these stocks also tend to come with out-sized volatility, so they're not for the faint of heart. And finding the very best among them is easier said than done.

To that end, we asked three Motley Fool investors to each pick a high-growth stock that they believe is poised to soar. Read on to learn why they chose Palo Alto Networks (NYSE:PANW), Criteo SA (NASDAQ:CRTO), and MedReleaf (TSX:LEAF).

Woman in suit drawing a line indicating exponential growth


The future of cybersecurity

Steve Symington (Palo Alto Networks): Make no mistake, Palo Alto Networks stock has already soared this year -- at least for opportunistic investors who took advantage of its temporarily plunge earlier this year. But as cyberthreats grow ever more sophisticated and demand for Palo Alto Networks' Next-Generation Security Platform grows, I think the stock could be just getting started.

Palo Alto Networks dropped more than 20% in a single day back in February, when sales-execution issues led the company to miss quarterly growth expectations and issue "conservative" forward-revenue guidance. But Palo Alto Networks has since revitalized its growth engine, handily beating expectations in each of its last two quarters after successfully restructuring its sales team.

Most recently, in late August, shares continued to climb as the company added more than 3,000 new customers -- more than ever before for any single quarter -- to bring its base to over 42,500. That helped sales climb 27%, to $509.1 million (versus guidance for $481 million to $491 million), which translated to nearly 40% growth in adjusted earnings per share, to $0.92 (versus guidance of $0.78 to $0.80).

But even more exciting is Palo Alto's impending launch of its new Application Framework, slated for early next year, which will introduce a new software-as-a-service model giving customers access to a suite of cloud-based security services and APIs from both Splunk and more than 30 leading security organizations. CEO Mark McLaughlin noted that the company has enjoyed "a lot of excitement and positive feedback" surrounding the framework, and argues it could disrupt the cyber-security industry yet again -- much in the same way their Next-Gen Security Platforms are already doing by overshadowing legacy firewall and antivirus solutions.

With shares of Palo Alto still down around 9% over the past year, I think long-term investors would do well to open or add to a position in Palo Alto Networks today.

Attractive, but risky 

Daniel Miller (Criteo S.A.): While high-growth stocks often come with a healthy amount of risk, investors prepared to accept those risks should take a look at Criteo, one of the leading advertising-technology companies in the digital-ad market. The company enables advertisers to publish marketing campaigns across multiple channels and devices with real-time analysis of the ads, so its clients can adjust campaigns accordingly. So far, the company has managed to add clients, improve its revenue, and improve its margins, which could improve even further once its investment in China and India bears more fruit as the number of mobile users increases.

In its recent third quarter, the company's revenue (excluding traffic-acquisition costs) jumped nearly 33% compared to the prior year. Its net income per share jumped an even healthier 38.1%, and cash flow from operations grew 41%. Criteo continues to rope in new clients, as well, adding 930 net new clients during the recent quarter, to bring its total to over 17,000, with an impressive client-retention rate of about 90% for its core product.

So far, so good for Criteo investors hoping to capitalize on growing digital ad dollars -- but this is a high-risk, high-reward investment. This year, Apple released its new Intelligent Tracking Prevention (ITP) feature on mobile devices, which is expected to negatively impact its revenue in the fourth-quarter by 8% to 10%. The risks are there, but if management can figure out how to adapt, Criteo also has the potential to soar.

Talk about growing like a weed

Sean Williams (MedReleaf): When I think of high-growth stocks, there's perhaps nothing more high growth than marijuana. The worry with marijuana is that it's illegal as a recreational drug everywhere in the world, save for Uruguay. However, a select few countries have legalized medical cannabis. One such company that could benefit is Canada's MedReleaf.

MedReleaf went public in May, raising capital that it's now using to expand growing capacity at its Bradford, Ontario facility. Last year, MedReleaf's revenue more than doubled, to $31.7 million, with the company generating $8.6 million in net income. That was a quadrupling of the profit that it delivered in 2016, and a major improvement from its nominal full-year loss in 2015. 

The company has benefited from the rapid growth of eligible medical patients in Canada. Health Canada reported in May that the number of eligible patients had been growing by about 10% per month, which alone has been enough to push MedReleaf healthfully into the black. 

But it's not just growing medical-cannabis sales alone that are its source of growth: It's the company's clientele. MedReleaf caters to a more affluent client and tends to carry more expensive dried cannabis strains. Even more so, it maintains the highest market share in Canada for cannabis oils. Since cannabis oils have a higher price point and margin, MedReleaf has found its niche as the grower for affluent clients, and it's resulted in a superior margin. 

To be clear, MedReleaf isn't cheap by any normal valuation measure. But it does have the potential to further expand its operations if Canada chooses to legalize recreational marijuana next year. If that's the case, another couple of years of doubling its sales and profits seems quite possible. Given its already steady profitability from a legal medical cannabis industry in Canada, MedReleaf could be worth a closer look.