The U.S. cannabis market is forecast to reach $115 billion by the beginning of the next decade, a better than six-fold increase in revenue from last year, if the federal government legalizes marijuana. It could still hit $50 billion just based on the current states where cannabis is legal. Medical marijuana use is permitted in 36 states, and there are currently 19 states (plus D.C.) that allow adult usage (South Dakota's legalization measure is undergoing legal challenges). 

The following two cannabis stocks are the best ones to buy in October to take advantage of the existing landscape, as well as the changes sure to come.

Marijuana leaf with stacks of gold coins

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Green Thumb Industries

Green Thumb Industries (GTBIF -4.95%) has been able to grow into one of the biggest, fast-growing multi-state operators (MSO) in the country by picking its locations carefully.

Primarily targeting high-dollar and limited-license markets, Green Thumb has ensured it can plant its flag to build its brands and develop loyal followings for them. It has a presence in 14 U.S. markets, including California, the world's largest marijuana market, with licenses to operate 111 retail locations in total. It also runs 16 manufacturing facilities. 

Green Thumb's leading dispensary chain, Rise, has stores in nine states, and it also operates a separate chain called Essence in Pasadena and Las Vegas, which are experiential in nature and provide high levels of customer interaction. That's key, because Green Thumb has arguably one of the best mixes of cannabis products available, deriving a majority of its revenue from higher-margin cannabis derivative products such as vapes, edibles, oils, and infused beverages. Derivatives also typically don't suffer the same supply chain problems as dried flower does.

Wall Street sees Green Thumb growing revenue at an astonishing compounded rate of 40% annually through 2024, achieving over $2.1 billion in sales, with GAAP net profits more than doubling every year.

Its stock is down 39% from its 52-week high, but analysts forecast it can hit $54 a share over the next year, which would be more than a double from current levels. Green Thumb Industries looks like a solid buy at this level.

People in a marijuana dispensary

Image source: Getty Images.

Trulieve Cannabis

Another profitable MSO, Trulieve Cannabis (TCNNF -1.15%) dominates the state of Florida, but now has a presence in about a dozen states, with over 125 operational dispensaries. Its recently completed acquisition of fellow MSO Harvest Health & Recreation introduced it to the state of Arizona, which analysts believe could become a $1 billion marijuana market in its own right; through the 15 dispensaries Trulieve picked up, it now has a commanding presence in the state.

That's important, because Trulieve has perfected a narrow-focused development strategy. It grew to be the largest MSO in Florida because it placed all of its attention on the Sunshine State and worked to grow to 94 dispensaries there, or one quarter of all the dispensaries operational in the state.

By saturating the market with its brand, it has become the go-to dispensary in Florida, and it achieved that while limiting the amount it needed to spend on marketing, giving it more bang for the buck. It now seeks to replicate that success in other states.

The problem facing Trulieve, of course, is the taint of corruption it carries following the conviction of the CEO's husband for fraud and bribery charges unrelated to the marijuana business. Although the charges involved his Florida property development company, not Trulieve, the overhang continues to weigh on the stock.

Shares of Trulieve are off 17% year-to-date, and they're down 50% from the highs hit in mid-March despite Wall Street still having a very positive outlook for the business. Revenue is forecast to hit more than $2.5 billion by 2025, a 37% compounded annual growth rate from the $522 million record last year. Profits are expected to expand at an equally impressive 28% annually, making this MSO another pot stock ready to be scooped up at a significant discount.