Lars Hagberg | AFP | Getty Images
Colleague Martin Henderson passes several cannabis plants on October 12, 2018 at Up's cannabis plant in Lincoln, Ontario.
The Canadian marijuana stocks Tilray and Canopy Growth have dropped for a second day on Tuesday. Aurora Cannabis has also fallen sharply after its debut on the New York Stock Exchange.
Traders blamed several reasons for selling off the big cannabis names. Several major conferences over the past few weeks, as well as legalization in Canada on October 17, sparked fierce competition and increased prices, a Canopy Growth shareholder told CNBC. Monday's suggestion may reflect a degree of profit-taking, investors said.
Investors could also cash before the launch of three major US cannabis companies on Canadian exchanges in the next month, the trader said.  Acreage Holdings, one of the largest vertically integrated multi-state cannabis operators in the US, announced earlier this year that the Series E financing round was completed and $ 119 million in capital secured. The company is expected to be listed on the Canadian Stock Exchange in early November.