U.S. securities regulators warned investors on Friday to be careful about getting involved in stock schemes involving small marijuana-related companies.
The Securities and Exchange Commission said it has already suspended trading in five different cannabis microcap companies in the past few months.
The latest crackdown Friday was against Fusion Pharm, a Denver-based company purportedly selling cultivation systems for marijuana.
Voters in Colorado and Washington legalized the possession and use of small amounts of marijuana for recreational use in 2012. They are also among 20 different states that permit the use of medical marijuana.
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The first recreational cannabis shops opened in Colorado in January.
"Given the attention that marijuana-related companies have attracted recently, we urge investors to exercise caution when looking at investments in this space," said Lori Schock, the head of the SEC's Office of Investor Education and Advocacy.