Curious what the buzz is about marijuana stocks? Look no further than the 33% sales growth in legal weed sales for North America in 2017, according to data from ArcView Market Research and BDS Analytics. Over the next four years, legal cannabis sales are expected to grow at a compound rate of 28%, hitting close to $25 billion in annual sales by the end of 2021. That's the type of growth that investors have a hard time overlooking. 

Likewise, we're witnessing a steady shift in the way the public views pot. Once considered a taboo topic, marijuana is now a regularly discussed issue by lawmakers, and has become more socially acceptable than ever before. Gallup's October 2017 survey found that an all-time record high 64% of respondents now favor legalizing weed nationally, up from just 25% in 1995.

A person holding cannabis leaves in their cupped hands.

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These pot stocks are set to deliver the most cannabis in 2019

However, the real excitement surrounds Canada and Canadian pot stocks, with our neighbor to the north on the verge of becoming the first developed country in the world to legalize recreational cannabis. With a vote set for Jun. 7, Canada's Senate and Prime Minister Justin Trudeau could put Canada on track to legally sell cannabis products to adults beginning in August or September. A legal adult-use market in Canada could generate $5 billion or more in annual sales.

As you might imagine, the expectation of legalization has cannabis growers clamoring for capital that they can use to expand their production capacity. The amount of bought-deal offerings, strategic partnerships, and acquisitions has been off the scale in recent months. In fact, a dive into the expected top cannabis producers at the end of January proved obsolete just days later as a result of dealmaking and partnerships.

Given that we now have better clarity following recent deal and expansion announcements, we're again going to look at the marijuana stocks offering the highest production and/or delivery capacity in 2019. While the data isn't perfect, it provides an increasingly clearer look at which pot stocks aim to be the industry's biggest players.

An indoor commercial cannabis grow farm.

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Aurora Cannabis: 240,000 to 270,000 kilograms

When it comes to marijuana stocks that have provided production guidance (key phrase!), none look to have surpassed Aurora Cannabis (NASDAQOTH:ACBFF). The company's second-quarter operating results suggest that it has anywhere from 240,000 kilograms to 270,000 kilograms of dried cannabis production capacity in 2019, depending on how quickly it receives licenses from Health Canada.

The bulk of Aurora Cannabis' production is expected to come from two facilities. First, its organic project known as Aurora Sky is an 800,000-square-foot, highly automated facility that's on track to be completed in mid-2018 and to generate more than 100,000 kilograms of dried cannabis a year. In terms of yield per square foot, Aurora Sky could be among the most efficient facilities in the world.

The other major deal involves a strategic partnership with Alfred Pedersen & Son in Denmark. Known as Aurora Nordic, this 1 million-square-foot facility will be capable of producing at least 120,000 kilograms of dried cannabis year.

As icing on the cake, Aurora Cannabis' acquisition of CanniMed Therapeutics for $852 million -- the priciest pot buyout in history -- should add 19,000 kilograms in fully funded capacity. Aurora Mountain, Aurora Vie, and Lachute should also each add between 4,000 kilograms and 4,800 kilograms per year, respectively. 

Jars of dried cannabis stacked on each other.

Image source: Getty Images.

Aphria: 230,500 kilograms

Coming in a close second to Aurora Cannabis is Aphria (NASDAQOTH:APHQF), which by the company's own admission is on track for 230,000 kilograms of production in 2019. However, this could be a conservative estimate.

Aphria's flagship project is its four-phase, more than $100 million buildout over 1 million square feet. When complete in January 2019, it'll be capable of producing 100,000 kilograms of pot annually. It's worth noting, though, that Aphria's peak production forecast has increased on a number of occasions, so it wouldn't at all be a surprise if it wound up yielding in excess of 100,000 kilograms a year when complete.

Secondly, Aphria entered into a strategic relationship with Double Diamond Farms in January 2018 that'll result in 120,000 kilograms of additional annual supply. Originally, Aphria had been planning on organically building out a 100-acre site, but that wouldn't have been complete until 2020. By forming a partnership with Double Diamond, Aphria more than doubled its capacity and lopped a year off its production time to do so in the process. 

Lastly, Aphria announced the acquisition of privately held Broken Coast Cannabis on Jan. 15 for $185 million, which is expected to have an annual output of 10,500 kilograms. Add that together and it's 230,500 kilograms, conservatively. 

A cannabis bud lying atop a messy pile of hundred dollar bills.

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Cannabis Wheaton Income Corp.: 230,000 kilograms

Cannabis Wheaton Income Corp. (NASDAQOTH:CBWTF) is where things start to get interesting. You see, Cannabis Wheaton isn't a traditional grower. Rather, it's a royalty-based cannabis company that provides up-front capital to growers of all sizes in return for a percentage of their yield. The capital that growers receive is used to expand capacity or a product line. Meanwhile, Cannabis Wheaton pays a below-market rate for the product it receives, then sells that product for market rates, thus pocketing the difference as profit. The company expects the average internal rate of return for its deals to be 60% or greater.

At the moment, Cannabis Wheaton has in the neighborhood of 15 deals on its books, which helps diversify its delivery of cannabis products both geographically throughout Canada and numerically. In other words, even if one or two of its licensed producers struggles to deliver what was intended, Cannabis Wheaton's operating results shouldn't suffer much at all.

According to a presentation from management, Cannabis Wheaton is on course to sell 230,000 kilograms of dried cannabis at market in 2019. Again, this assumes that all of its partners remain on track and budget with their own projects, and that Cannabis Wheaton has no trouble selling the product it receives. Though the royalty model is highly capital-intensive up front, it could prove very lucrative over the long run. 

Cannabis plants growing in an indoor facility under special lights.

Image source: Getty Images.

MedReleaf: 140,000 kilograms

Since going public last year, MedReleaf (NASDAQOTH:MEDFF) had primarily focused on organically building out its Bradford, Ontario, facility. When complete, Bradford will span 210,000 square feet and push MedReleaf's total annual output, along with its Markham facility, to 35,000 kilograms.

Of course, 35,000 kilograms of annual capacity wasn't going to cut it with deal escalation ongoing in the industry. On Feb. 26, MedReleaf announced that it was acquiring 164 acres of property in Ontario for $17 million in cash and 225,083 common shares of stock.

On 69 acres of property exists the Exeter Facility, which is an existing greenhouse that the company plans to retrofit to harvest cannabis. When complete, Exeter should be capable of producing 105,000 kilograms of cannabis a year, which would push MedReleaf's fully funded capacity to 140,000 kilograms.

What's more, the remaining 95 acres can be built out to accommodate more greenhouse facilities in the future. MedReleaf estimates that the remaining acreage could house a facility that's one and a half times larger than Exeter, which would presumably be capable of 150,000 kilograms of annual capacity, if not more. In short, this latest acquisition really put MedReleaf on the map as a major player. 

A panorama view of a large cannabis grow facility.

Image source: Getty Images.

Canopy Growth Corp.: approximately 300,000 kilograms

Last but not least, we have Canopy Growth Corp. (NASDAQOTH:TWMJF), the wildcard of the group. You've probably been wondering where the largest marijuana stock in the world by market cap fits into all of this and why I hadn't mentioned it yet. The reason is simple: Management is tight-lipped about its annual production capacity, and is currently the only grower among the big five to not have offered guidance to Wall Street. In other words, no one knows. But that won't stop me from making an educated guess.

What we do know is that Canopy Growth has seven operating grow facilities currently spanning 665,000 square feet of growing space. It's expanded this growing capacity organically, as well as through acquisitions. Its purchase of Mettrum Health in January 2017 being a perfect example of the latter.

We also know from the company's third-quarter operating results that it has a ridiculous 3.4 million square feet of greenhouse facilities under construction or in development in British Columbia. The timeline for completion is anyone's guess, but my suspicion is that most of this capacity will be on line and producing in 2019. 

What we don't know are what sort of yields to expect from this production, what percentage of production is devoted to dried cannabis versus cannabis oils, and when this production will officially be on line. However, using a conservative estimate of 100,000 kilograms of yield for every 1 million square feet of production capacity, it's not hard to see Canopy Growth getting to 300,000 kilograms of production in 2019.

Sean Williams has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.