The mania for all things pot-related is in full swing, but some investors are choosing to watch from the sidelines.

Investors pulled US$45.9 million from the Horizons Marijuana Life Sciences Index (HMMJ.TO) exchange-traded fund last week, the biggest weekly outflow on record. At the same time the world’s largest marijuana ETF rose 12 per cent, the most in four weeks.

Shares of marijuana-related companies have skyrocketed ahead of the full legalization of recreational weed in Canada next month, but for some investors the volatility in the pot stocks have been too much to take. Tilray Inc. (TLRY.O), the cannabis company that saw a nearly 200-point swing last week, is poised for a third daily loss, the longest streak of declines since July, after opening 18 percent lower on Monday on trade below $100 a share. The stock is down 3.2 per cent at 10:23 a.m. in New York. New Age Beverages Corp., which soared 287 per cent last week, plunged 20 percent Monday.

Canopy Growth Corp. (WEED.TO) fell as much as 3.5 per cent in the U.S. and 4.2 per cent in Canada on Monday. Cronos Group Inc. (CRON.TO), which rallied 21 per cent last week, fell 1.9 per cent after plunging 6.9 per cent at the open.

“There certainly seems to be a bubble in the cannabis stocks, but once the bubble pops, the survivors will be great stocks, just like the survivors of the dot.com bubble have been,” said Matt Maley, an equity strategist at Miller, Tabak & Co. “In fact, we think that any future wash-out in this industry will provide an unbelievable buying opportunity.”

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