Short-squeeze plays and tech stocks appear to be the favorites for Robinhood investors right now. However, there's another group of stocks high on the list as well.

Investors on the free trading platform definitely appear to be enamored with marijuana stocks these days. Here are the top five most popular pot stocks on Robinhood -- and whether any of them are great picks to buy. 

Cannabis leaf on $100 bills

Image source: Getty Images.

Robinhood's top five pot stocks

Robinhood regularly updates its list of the 100 most popular stocks. This list is based on which stocks are most widely held by its customers. The following five pot stocks ranked the highest:

Stock

Market Cap 

Overall Popularity Rank

Sundial Growers (SNDL 1.80%) $2.4 billion 4
Aphria (APHA) $6.5 billion 12
Aurora Cannabis (ACB -5.41%) $2.1 billion 19
OrganiGram (OGI 1.30%) $943 million 25
Canopy Growth (CGC 0.58%) $12.7 billion 32

Data source: Robinhood. All data as of March 19, 2021.

These aren't the only cannabis stocks in Robinhood's top 100, by the way. Tilray (TLRY) currently ranks at No. 39. Cronos Group is No. 51 on the list. And Hexo lags behind at No. 70.

It's not a coincidence that all of these stocks are Canadian cannabis producers. U.S.-based cannabis companies can't list their shares on major U.S. stock exchanges. Since Robinhood doesn't support trading for most over-the-counter stocks, these U.S. marijuana stocks can't be bought or sold on the platform. 

How they compare

Another thing that all five of the most popular pot stocks on Robinhood have in common is that they've performed quite well so far in 2021. Three of them have been sizzling hot.

SNDL Chart

SNDL data by YCharts

All five companies have the same opportunities in the Canadian cannabis market. However, Canopy Growth and Aphria appear to be in the strongest position. Canopy's market share in the Canadian recreational market stands at 15.7%. After Aphria's merger with Tilray, which is expected to close in the second quarter, the combined company anticipates having a market share of 17.3%. 

There's a wide gap between the companies in international markets. Aphria's wholesale operations in Germany give it a big advantage. Canopy Growth and Aurora are also major players in European medical cannabis markets. Sundial and OrganiGram, on the other hand, don't have international operations at this point.

The biggest opportunity of all is in the United States. None of these Canadian companies can enter the U.S. cannabis market as long as marijuana remains illegal at the federal level. However, it's possible that major cannabis reform could change this status in the not-too-distant future.

Canopy Growth stands out from the pack in readiness to expand into the U.S. cannabis market. The company has options to acquire Acreage Holdings and a stake in Terrascend, both of which have U.S. cannabis operations. Canopy also has a close partnership with its largest shareholder, Constellation Brands, a leader in U.S. adult beverage markets.

Are they buys?

Ironically, the least attractive of these top five Robinhood stocks in my view is the most popular one. Sundial Growers faces the steepest challenge. The company's revenue fell year-over-year in the fourth quarter. Sundial also posted another big net loss.

Aurora Cannabis isn't in a great financial position, either. It was once the biggest cannabis stock in the world based on market cap. However, Aurora continues to lose a lot of money. Like Sundial, the company has also diluted its stock significantly to raise additional cash.

My view is that OrganiGram is definitely a Canadian pot stock to watch. It has generated positive cash flow in two of its past three quarters. I'm not ready to call the stock a solid buy just yet, though.

There are two of these popular pot stocks that could be buys for some investors, in my opinion. I think Canopy Growth has what it takes to be successful over the long run, especially if the door opens to enter the U.S. cannabis market. 

If you like arbitrage plays, Aphria could be one to consider over the short term. Because of the structure of its merger agreement with Tilray, there's a pretty good possibility the stock could rise some in the near future.

However, I think the best cannabis stocks of all to buy aren't included in the Robinhood top 100 list. Several U.S. pot stocks offer even better risk-reward propositions than any of their Canadian counterparts.