Following years of promises from Prime Minister Justin Trudeau, and months of debate between Canada's Senate and House of Commons, legal marijuana for adult purchase is set to hit dispensary shelves for sale in exactly three weeks. In legalizing recreational cannabis, our neighbor to the north is opening the door to an industry that could generate billions of dollars via domestic and export sales.

However, there are few, if any, guarantees that shareholders will benefit right out of the gate, despite lofty growth expectations for the cannabis industry. A quick screen of some of the most popular marijuana stocks yields five that have a very good chance of producing a full-year loss in fiscal year 2019 (most marijuana stocks are operating on a non-traditional fiscal calendar).

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Canopy Growth Corp.

Although Canopy Growth Corp. (NYSE:CGC) is possibly the most well-rounded of all Canadian marijuana growers, it's still projected to lose money in fiscal year 2019 by Wall Street. The reason is because of its need to expand the company's infrastructure in international markets, as well as build up its existing brands and marketing strategy. Canopy Growth also needs to finish the expansion of its 5.6 million square feet of growing space in British Columbia, which is costing a pretty penny.

The good news is that Canopy Growth has more than enough capital to complete its expansion in B.C. and internationally. On Aug. 15, Constellation Brands, the producer of the Modelo and Corona beer brands, announced that it'd be taking a $3.8 billion equity stake in Canopy Growth. With well over $4 billion in cash on its balance sheet, Canopy has more than enough capital to beef up its abroad presence.

GW Pharmaceuticals

U.K.-based GW Pharmaceuticals (NASDAQ:GWPH) made waves on June 25 when it became the first drugmaker in history to get a cannabis-derived medicine approved by the U.S. Food and Drug Administration (FDA). Considering that GW Pharmaceuticals' lead drug Epidiolex -- a cannabidiol-based oral solution for two rare types of childhood-onset epilepsy -- dazzled in phase 3 trials and earned a unanimous recommendation for approval from the FDA's advisory panel, it's not all that surprising that it was approved.

Eventually, Epidiolex is expected to push GW Pharmaceuticals into the black. But in the interim, the high costs associated with launching and marketing a new drug, along with ongoing research and development expenses, are liable to keep the company in the red for the foreseeable future.

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Tilray

Day-trading darling Tilray (NASDAQ:TLRY), which briefly made a run at a $28 billion market cap last week, is another popular pot stock that's unlikely to produce a profit in fiscal year 2019. Although Tilray is looking to expand abroad, just like Canopy Growth, its near-term focus will probably be on capacity expansion. And the high costs associated with this expansion are what will likely keep it in the red.

According to the company's S-1 prospectus filing with the Securities and Exchange Commission in June, it looks to have 912,000 square feet of combined growing and processing capacity complete by the end of 2018 (56,000 square feet of this is for processing). However, Tilray could potentially cap its growing capacity at approximately 3.6 million square feet, giving it the ability to quadruple its production. As the company spends to up capacity, losses could continue, even as sales soar. That's certainly something for cannabis speculators to consider when investing in Tilray.

The Green Organic Dutchman

Even though there are no Wall Street sales and profit estimates for The Green Organic Dutchman (OTC:TGODF), I'm more than willing to go out on a limb and predict a net loss for fiscal year 2019. The reason being that the company, like Tilray and Canopy, will be busy expanding its production capacity, and therefore spending a small fortune doing so.

The Green Organic Dutchman had two projects two worry about when it debuted as a publicly traded company earlier this year: its flagship Valleyfield property in Quebec, which is expected to yield 102,000 kilograms when at full capacity, and its Ontario property, with 14,000 kilograms of production when fully operational. Now, the company has a partnership with Epican Medicinals in Jamaica and Queen Genetics/Knud Jepsen in Denmark, and has noted its intent to build a 287,245-sqiare-foot facility on its Valleyfield property for beverage and edible production. Although cannabis-infused beverages and edibles won't be legal come Oct. 17, Parliament is widely expected to approve new forms of consumption beyond dried cannabis and cannabis oils next year.

Two rows of trimmed cannabis partially covering a row of hundred dollar bills.

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KushCo Holdings

Last, but not least, popular ancillary marijuana stock KushCo Holdings (OTC:KSHB) is expected by Wall Street to continue losing money in fiscal year 2019, despite the fact that preliminary sales for its recently ended year rose 171% to $51 million. KushCo has been busy in the acquisition department in recent months, and it'll be spending liberally to establish itself as a go-to player in niche markets. 

Most investors are probably aware of KushCo as the go-to packaging solutions expert for the cannabis industry. With Health Canada setting pretty stringent regulations as to what rules need to be followed in order to get product onto dispensary shelves, KushCo will play a key role in supplying that packaging.

However, it's also made a push into the branding and marketing field, as well as hydrocarbon gas and solvent production, via acquisitions. With pot stocks moving into the branding phase of their development, KushCo Holding aims to be a source they'll turn to. In addition, hydrocarbon gases are instrumental in cannabis oil production, placing KushCo in an advantageous position as a pivotal middleman. Though the losses may continue in the interim, it's an intriguing pot stock to watch.