The North American Marijuana Index, a stock index that tracks the top performing cannabis stocks in the U.S. and Canada, decreased 15% in May as stocks sold off in both markets. This marks the worst performing month for the North American Marijuana Index since December 2015.

The North American Marijuana Index is a combination of the U.S. Marijuana Index and the Canadian Marijuana Index.

U.S. Marijuana Index

The U.S. Marijuana Index decreased 15% in May, with 17 of its 20 constituents posting losses for the month. The broader U.S. market saw mixed results with the Dow Jones Industrial Average relatively unchanged with a 0.3% gain and the Russell 2000 ending the month down 2.2%. Overall, the U.S. Marijuana Index is down 29% in 2017 year-to-date.

After decreasing 11% in April, the U.S. Marijuana Index saw a small 6% rebound in the first few days of May. This quickly reversed as the U.S. Marijuana Index trimmed 15% in the following week as the Trump Administration extended the Rohrabacher-Blumenauer Amendment but issued a signing statement that created uncertainty about whether the Department of Justice will adhere to the amendment preventing it from prosecuting medical marijuana programs.

Nine constituents on the U.S. Marijuana Index lost more than 20% during the month. Only three constituents incurred gains for the month: Marapharm Ventures Inc. (CSE:MDM, OTCQB:MRPHF), Golden Leaf Holdings Ltd. (CSE:GLH, OTCQB:GLDFF), and GrowGeneration Corp. (OTCQB:GRWG).

Canadian Marijuana Index

The Canadian Marijuana Index decreased by 14% in May after reaching an all-time high of 359.19 in April. This compares to a 1% decrease in the S&P/TSX Venture Index, Canada’s leading small-cap index. All 12 constituents on the Canadian Marijuana Index experienced losses for the month.

Constituents on the Canadian Marijuana Index saw a 67% drop in average daily trading volume in May compared to April as trading cooled down in the wake of the Canadian government’s recreational legalization announcement on April 13.