REUTERS/Christinne Muschi

Cowen, the first major Wall Street bank to follow marijuana stocks, has been publishing recommendations on Canopy Growth and Tilray, and on Tuesday added Cronos Group and Aurora Cannabis to its coverage.

The four Canadian cannabis producers were listed in the US last year, prompting investors to pour money into the industry.

Also in the last year, a wave of recreational-marijuana legalization has triggered companies in other fields, such as beverage and tobacco, to enter the space.

Cowen, the first major Wall Street bank to follow marijuana stocks, on Tuesday added two popular names to its coverage universe.

The firm had been publishing recommendations on Canopy Growth and Tilray, and is now also writing research on Cronos Group and Aurora Cannabis.

The four Canadian cannabis producers were listed in the US last year, prompting investors, especially younger ones, to pour money into the industry. On Robinhood, a free-trading app popular among millennials, Aurora has outranked all other stocks in terms of the number of users who own shares.

Also in the last year, a wave of recreational-marijuana legalization - including in Canada and the state of Michigan - has triggered companies in other fields, such as beverage maker Constellation Brands and tobacco giant Altria to enter the space. Constellation Brands and Altria invested in Canopy and Cronos respectively.

Driven by the strong demand for insight into marijuana stocks, Cowen's Vivien Azer became the first Wall Street senior analyst to cover the emerging cannabis sector, and leads the marijuana research team at the firm.

Last month, Jefferies became the second major Wall Street bank to track the industry, initiating coverage on seven cannabis companies.

Here's what Cowen says about Cronos Group and Aurora Cannabis. The potential upside is the difference between the bank's price target and where shares were trading as of March 4: