The stock market has done well to begin 2019, and the cannabis industry in particular has seen explosive gains. After a lackluster 2018 for many of the largest players in big marijuana, most of the highest-profile companies in the budding cannabis industry have rocketed higher, and some have even made their way to new record levels.

Like any investing trend, though, some companies are doing better than others. In fact, there's one stock among big marijuana players that's seen only the most modest of share-price increases in 2019, and that has some cannabis investors wondering what that means both for that company in particular and for the sector in general.

ACB Chart

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Investors buy into cannabis collaboration

A look at the chart above shows that the two big winners so far in 2019 happen to be companies that have made the most significant partnerships with companies outside the cannabis industry. Canopy Growth (NYSE:CGC) has had a close relationship with Constellation Brands (NYSE:STZ) for more than a year now, while Cronos Group's (NASDAQ:CRON) recent deal with tobacco giant Altria (NYSE:MO) dramatically increased its exposure within the industry.

Canopy's gains stem from a couple of factors. First, shares of the marijuana company had taken an especially hard hit as 2018 came to a close, and so to an even greater extent than the rest of the industry, its stock was poised for a bounce. More importantly from a fundamental perspective, Canopy made a smart move, taking advantage of the passage of farm-related legislation in the U.S. to announce plans to build a hemp production facility in New York. By building a presence in the U.S. market, Canopy will be better positioned to make more dramatic moves if cannabis becomes legal nationwide.

Cronos also looks poised to take advantage of the hemp opportunity, and having Altria in its corner is an invaluable asset. Cronos is much smaller than Canopy Growth, but it's worked hard to make its name in the Canadian cannabis market. Altria's experience in tobacco production and distribution should help Cronos become more efficient with its own business, and the availability of additional capital gives Cronos the chance to scout out more strategic combinations. That could prove particularly useful as more U.S. jurisdictions look at legal marijuana.

Check out the latest Canopy Growth, Cronos Group, Altria, and Constellation Brands earnings call transcripts.

Inside of greenhouse with rows of cannabis plants and lighting and fans.

Image source: Getty Images.

The middle of the 2019 pack

The 25% to 35% gains that Aphria (NYSE:APHA) and Aurora Cannabis (NYSE:ACB) have seen so far in 2019 are only disappointing in comparison to Cronos and Canopy. For the most part, investors seem optimistic about these two companies as well, although that enthusiasm has been tempered to an extent.

Aphria has put itself in a solid position to benefit from rising cannabis demand, but some worry that it hasn't been able to ramp up production as much as its peers. Aphria's capacity is likely about half what Canopy can produce, and Aphria has seen its costs rise recently. A hostile takeover attempt by a U.S. company in the marijuana industry has drawn some interest, but Aphria hasn't attracted a full-blown partner like Altria or Constellation Brands.

Similarly, Aurora Cannabis is seeking to be a major growth player in marijuana, and its work to boost production capacity has paid off. Yet some are annoyed at the fact that Aurora uses so much stock in making acquisitions, as it dilutes current shareholders to do so. A growth-at-all-costs mentality makes sense in the initial frenzy of a high-growth industry like cannabis, but without the discipline to be smart about capital allocation and using equity for strategic purchases, Aurora could disappoint early investors.

Check out the latest Aphria earnings call transcript.

One significant laggard

Finally, Tilray (NASDAQ:TLRY) has been notable in the fact that its shares have barely budged in 2019. Unlike Aurora, Tilray has been more measured in its approach toward strategic moves, making acquisitions that fit as well as possible with its overall goals. Yet investors haven't been impressed with the overall direction that Tilray has gone.

For instance, in December, Tilray announced a collaboration with Anheuser-Busch InBev for joint research on cannabis-infused beverages. Yet the beer giant wasn't willing to put its wallet where its mouth was, failing to make any investment in Tilray stock whatsoever. With such a closely defined partnership that doesn't seem to envision equity investments, Tilray and A-B InBev don't seem to have the same ideas in mind as rivals like Canopy and Cronos.

Moreover, Tilray still seems overvalued by many measures. Despite the huge decline the stock suffered during the autumn months of 2018, Tilray still trades far above its IPO price. That makes it less of a bounce-back candidate than the other big marijuana companies.

Check out the latest Tilray earnings call transcript.

Keep your eyes on the leaf

Competition remains fierce in the cannabis industry, and these five companies will keep gunning for position among the top marijuana stocks in the business. Don't be surprised if current share-price trends change, because all of these big marijuana players are fighting hard to stake their claims to the fast-growing worldwide opportunity in cannabis.