What happened

Shares of major Canadian marijuana stocks enjoyed yet another day of nice gains today. Shares of Canopy Growth (CGC -3.01%) were up 8.2% as of 11:42 a.m. EDT Friday. Tilray (TLRY) stock rose 10.3% higher. Cronos Group (CRON 0.81%) was the biggest mover of the three, with its share price soaring 15.1%. Earlier in the morning, all three stocks were up by double-digit percentages.

There weren't any new developments for any of these leading marijuana growers. But it appears that institutional investors could still be buying the stocks after Constellation Brands announced a $4 billion investment in Canopy Growth, further legitimizing the cannabis industry.

Tiny figures pushing wheelbarrows with marijuana buds on top of money clip with $20 bills

Image source: Getty Images.

So what

One-day jumps are great, but Canopy, Cronos Group, and Tilray are on a roll. All three stocks also jumped by double-digit percentages on Monday. Over the last two weeks, each of the marijuana stocks has risen close to 60%.

Part of the momentum certainly stems from Canopy's huge deal with Constellation Brands. Some investors are likely waiting for another major alcoholic beverage maker to step forward into the cannabis market. Cronos and Tilray would almost certainly be among the top candidates if that were to happen.

Another important factor is that the opening of Canada's recreational marijuana market is right around the corner. The country is scheduled to begin allowing sales of recreational cannabis for adult use on Oct. 17, 2018. Earlier this week, Ontario, which has the largest population of all of Canada's provinces, announced supply agreements with 26 licensed producers, including Canopy Growth, Cronos Group, and Tilray.

Other Canadian marijuana stocks have also enjoyed big moves, but Canopy Growth, Cronos Group, and Tilray have stood above the pack. The most likely reason behind this is that they're the only Canadian marijuana stocks that are listed on U.S. exchanges.   

Now what

If we're indeed seeing institutional investors move into the top Canadian marijuana stocks, it could take a while for them to reach their target positions. While their buying continues, it will likely attract other investors to the stocks as well.

It's important to remember, though, that enormous growth expectations are already baked into the share prices of Canopy Growth, Cronos Group, and Tilray. Any bumps along the way in generating the anticipated growth could cause these stocks to drop as quickly as they've risen.