Legalizing marijuana is a controversial topic, but it is proving to be a very profitable investment.

In fact, in just the last two years, investors have watched as:

• Canopy Growth (TWMJF) rocketed from $7.50 to $25
• OrganiGram (OGRMF) jumped from $1.50 to highs of $4.50
• Aphria Inc. (APHQF) ran from $4 to $20
• GW Pharmaceuticals (GWPH) popped from $119 to $144
• Kush Bottles (KSHB) soared from $3 to $8.50

And the runs are far from over.  In fact, there are plenty of catalysts that could force marijuana stocks even higher, creating sizable opportunities.

Right now, more than 29 U.S. states plus Washington, D.C. approved marijuana’s medicinal use.  Eight states have approved its recreational use.  New Jersey may approve its recreational use this year, as Governor Phil Murphy promotes a bill that would legalize it.  Michigan may approve it, as well.

On July 26, Oklahoma will vote on State Question 788, which proposes legalization of medical marijuana and the establishment of a state system to tax and regulate its use. As the legalization boom continues, some analysts believe the marijuana industry could be worth well over $50 billion by 2021.

Even Canada is considering legalizing its use across the country by August 2018.  If that happens, the country could see millions, if not billions in sales.

If legalized, analysts say by 2021 Canada could have nearly four million recreational marijuana users, creating a monstrous $4.5 billion industry. The industry could balloon to $8.7 billion shortly after, as marijuana retail sales, just in Canada. are likely to surpass beer, wine and spirit sales combined. That’s big money.

Dubbed the “Green Rush,” entrepreneurs, investors and producers are tripping over one another to take part.  And it’s opening massive opportunities for smart investors.

“This is a multibillion-dollar industry going from black to white,” says Vahan Ajamian, an analyst with Beacon Securities in Toronto.  “It’s like the end of alcohol prohibition in the US. It’s a once in a generation kind of investment opportunity.”

Just in case you’re concerned about these speculative stocks, consider this – legal pot sales could hit $50 billion by 2021.

In short, controversial or not, marijuana stocks have been – and could be – one of the most profitable investment opportunities of the year.