Few if any industries have been as impressive over the past couple of years as the legal cannabis industry. With Canada becoming the first industrialized country in the world to wave the green flag on adult-use pot, and more than 40 countries giving the OK to medical cannabis in some capacity, Wall Street and investors are clearly expecting big things from this industry.

How do we know this? Look no further than marijuana stock valuations. Once considered long-shot investments as recently as early 2017, there are now 14 pot stocks with a market cap of at least $1 billion (sorry, OrganiGram Holdings, you missed the cut by just $3 million), through April 25. Let's take a brief look at the largest publicly traded pure-play marijuana stocks in the world, along with their respective market caps.

A handful of cannabis buds lying atop a messy pile of cash bills.

Image source: Getty Images.

1. Canopy Growth: $16.64 billion

With few exceptions, Canopy Growth (NASDAQ:CGC) has been a fixture as the largest pot stock in the world for much of the past couple of years; and for good reason. Canopy has more cash and cash equivalents at its disposal (thanks to a huge $4 billion equity investment from Constellation Brands) than any other pot stock, and is projected to be Canada's second-largest annual producer, with more than 4.4 million square feet of its peak 5.6 million square feet of cultivation space already licensed. It's also no slouch in the branding and international expansion department, with the most recognized brand in Canada (Tweed) and access to over a dozen overseas markets.

2. Aurora Cannabis: $9.22 billion

Aurora Cannabis (NASDAQ:ACB) is arguably the most popular pot stock among millennials. More importantly, it's also forecast to be the leading Canadian producer, by quite a bit. Though management projects more like 500,000-plus kilos of peak annual pot production a year at full capacity, yours truly foresees up to 780,000 kilos a year by 2022. A good portion of this production is the result of Aurora's aggressive acquisition strategy that saw it gobble up MedReleaf for $2 billion, CanniMed for $850 million, and South America's ICC Labs for $200 million. As the icing on the cake, Aurora Cannabis also has a presence in more countries (24) than any other pot stock.

3. Cronos Group: $5.52 billion

Having recently moved into the No. 3 spot, Cronos Group (NASDAQ:CRON) has benefited from a $1.8 billion equity investment from tobacco giant Altria, which closed in March. The investment gave Altria a nondiluted 45% stake in Cronos, but more importantly supplied Cronos with the working capital it needs to expand its production capacity, diversify its product line, build up its brands, and move into overseas markets. With perhaps 120,000 kilos of peak annual output, and a presence in only four overseas countries, Cronos definitely needed this cash to execute on its long-term strategy.

A vial of Epidiolex next to its packaging and two droppers.

Image source: GW Pharmaceuticals.

4. GW Pharmaceuticals: $4.99 billion

The only pure-play cannabinoid drug developer of the bunch is GW Pharmaceuticals (NASDAQ:GWPH). In June 2018, GW Pharmaceuticals' lead drug, the oral cannabidiol (CBD)-based therapy Epidiolex, was approved by the U.S. Food and Drug Administration (FDA). This followed a unanimous recommendation for approval from the FDA's panel just a weeks earlier. Epidiolex wound up reducing seizure frequency from baseline by 30% to 40% in multiple late-stage trials for patients with Dravet syndrome or Lennox-Gastaut syndrome, and now slides in as the only approved treatment for Dravet syndrome.

5. Tilray: $4.96 billion

How the mighty have fallen. Once having briefly dethroned Canopy Growth for the top spot, Tilray (NASDAQ:TLRY) has seen its market cap retrace to below $5 billion. Though Tilray has done an impressive job of building up its medical cannabis brands in Canada, as well as expanding into new markets, a recently announced strategy shift that'll see Tilray focusing on the European Union and the United States, while deemphasizing Canada, has left investors scratching their heads. Additionally, with only around 100,000 kilos in peak output at the moment, investors are clearly wondering when Tilray will up its production capacity.

6. Curaleaf Holdings: $4.82 billion

In the sixth spot, but within striking distance of a top-three position, is Curaleaf Holdings (OTC:CURLF), the largest vertically integrated dispensary operator in the U.S., at least by market cap. Vertically integrated retailers like Curaleaf control their entire supply chain, which is necessary to keep costs down, ensure quality control, and stay compliant with U.S. state and federal cannabis laws. Right now, Curaleaf has 43 open retail stores, 12 grow farms, and 11 processing sites, but is aiming for nearly 70 open dispensaries by the end of the year. It also recently struck a deal to sell some of its CBD-rich hemp products in CVS Health.

A large dispensary store sign, with a cannabis leaf and the word dispensary written underneath it.

Image source: Getty Images.

7. Harvest Health & Recreation: $2.67 billion

Even though there's a pretty substantial drop-off in market cap between Curaleaf at No. 6 and Harvest Health & Recreation (OTC:HRVSF) at No. 7, it doesn't make what Harvest Health has done any less impressive. Harvest Health may only have 10 retail locations open in four states right now, but a number of major acquisitions, including the $850 million all-stock deal to buy privately held Verano Holdings, will catapult its number of retail, cultivation, and processing licenses higher. Assuming all existing deals close, Harvest Health will have 213 total licenses, including the right to open 130 retail locations, which is tops among publicly traded dispensary operators.

8. Acreage Holdings: $2.54 billion

Perhaps it's no surprise that the eighth-largest pot stock is Acreage Holdings (OTC:ACRGF), a U.S. vertically integrated dispensary operator that agreed to be conditionally acquired by Canopy Growth for $3.4 billion in a cash-and-stock deal. The condition being that the U.S. federal government legalize cannabis, which could happen soon, in a few years, or not at all. Acreage holds licenses for close to seven dozen retail stores in the U.S., and has the largest geographic presence of any vertically integrated cannabis company at 20 states, assuming all existing acquisitions close.

9. Aphria: $1.93 billion

Having been hurt by a short-seller report in early December and management turnover, Aphria (NASDAQ:APHA) has slipped all the way back to a sub-$2 billion market cap. But Aphria still possesses what could be the third-largest production portfolio in Canada, with an expected 255,000 kilos a year when at full capacity. Aphria's management team has also regularly emphasized generating positive EBITDA. If the company can gain licensing and sales approval for its largest partnered facility, Aphria Diamond, and return to profitability, Aphria has a shot to regain the trust of investors.

Two miniature shopping carts filled with a cannabis flower and cannabis oil products.

Image source: Getty Images.

10. Cresco Labs: $1.82 billion

At the No. 10 spot we find yet another U.S. vertically integrated cannabis dispensary operator in Cresco Labs (OTC:CRLBF). Although Cresco has a relatively small number of open locations, it did announce a game-changing, $823 million all-stock acquisition on April 1 of Origin House. Origin House is a leading distributor of cannabis in California, which is a fancy way of saying that it'll help Cresco Labs get its branded cannabis into more than 500 of California's dispensaries. While not as well known as the other dispensary operators, Cresco should make a name for itself if the Origin House deal closes.

11. Charlotte's Web Holdings: $1.73 billion

Charlotte's Web Holdings (OTC:CWBHF) is a manufacturer and distributor of hemp-based products containing CBD, the nonpsychoactive cannabinoid best known for its perceived medical benefits. Having had its products in close to 3,700 stores at the end of 2018, retail doors are literally, and metaphorically, wide open for Charlotte's Web following the legalization of hemp and hemp-based products in December via the signing of the Farm Bill. Charlotte's Web is also, arguably, one of the most profitable pot stocks right now.

12. HEXO: $1.51 billion

Although it's been tugged and pulled every which way by Wall Street analysts, HEXO (NASDAQ:HEXO) finds itself in the enviable position as the 12th-largest pot stock by market cap. In April 2018, HEXO landed what's still the most impressive long-term cannabis supply deal in Canada: a 200,000-kilo supply deal with Quebec over five years, with the option for a sixth year. It also somewhat recently announced the acquisition of Newstrike Brands for $197 million, which will be responsible for boosting its peak annual output from 108,000 to 150,000 kilos, making HEXO a top-six producer in Canada.

A tipped over prescription bottle lying atop a doctor's prescription pad.

Image source: Getty Images.

13. Trulieve Cannabis: $1.44 billion

Continuing the theme of U.S. vertically integrated cannabis dispensaries, we next have Trulieve Cannabis (OTC:TCNNF). Trulieve has been laser-focused on Florida, with 27 open dispensaries currently located in the Sunshine State. Then again, this has worked out nicely for Trulieve, since it's been one of a very few pot stocks to have delivered an operating and bottom-line profit. Trulieve is in the early stages of building up a presence in California and Massachusetts, but for now is all about those Florida retirees needing medical cannabis products.

14. MedMen Enterprises: $1.32 billion

Last, but not least, yet another vertically integrated dispensary operator in MedMen Enterprises (OTC:MMNFF). Once one of the largest dispensary stocks, MedMen's share price has tumbled on the heels of some pretty large expansion-based losses. MedMen is currently in the process of acquiring privately held PharmaCann for $682 million in an all-stock deal, which, when complete, will boost its presence to a dozen states and up its retail license count to 82. As a company with retail sales per square foot to rival Apple stores, MedMen is hoping for a return to glory sooner rather than later.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.