Bloom off of pot stocks on Wall Street

Wall Street seems to be losing its appetite for pot.

Marijuana stocks were high flyers - so to speak - after Colorado and Washington states legalized pot sales and several other states announced they may legalize sales or decriminalize possession. Shares in about 20 marijuana-related companies began soaring, with some gaining more than 500% off 52-week lows.

But marijuana mania continues to fade as investors realize there's more smoke than fire at many companies, which show "pot-tential" but little actual revenue. CannaVest, which specializes in industrial hemp production, had climbed to $180 a share last month. After dropping 11% to to $61.45 Thursday, it's lost nearly two-thirds of its market value.

Earlier in the day the Las Vegas based company said it is "continuing its plans to be in the forefront of establishing a domestic industrial cultivation and production infrastructure" and that it is "partnering and collaborating on research and pilot projects in states where hemp has been legalized."

Vape Holdings, which markets marijuana vaporizers and e-cigarettes, dropped 9.3% to $29.01. It traded more than 40% higher earlier this month.

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Many pot stocks are thinly traded "pink sheet" stocks, little followed by stock analysts and able to forego the financial reporting requirements of larger, more established companies.

Among them, GreenGro Tech dropped 13% to 58 cents a share Thursday and is now off more than 50% from its January $1.20 peak. Cannabis Sativa lost 11% to $10.35. Its down 43% from an $18 high.

Medical Marijuana fell 4% to 31 cents a share and is now down 35% from a 52-week high. Canabusiness Group lost 9 % to 27 cents, Since peaking at 48 cents Tuesday, it's dropped 44%. Hemp Inc., which traded at 34 cents Feb. 5, closed Thursday at 12 cents, a 65% fall.

The non-profit Financial Industry Regulatory Authority say! s investors should remain wary and research pot stocks before they consider buying.

"These stocks can be incredibly volatile and you can see significant prices swings with low trading volume,'' says Gerri Walsh, head of FINRA's investor education. FINRA issued an alert last August, saying scammers were touting the stocks, riding fat gains and then dumping them.

The lone pot-related stock to maintain its relative high: GW Pharmaceuticals, up 2.5% to $70.20 and down just 19% from its peak. The London-based biotech firm is developing therapeutics from cannabinoids to treat epileptic seizures, Type 2 diabetes and schizophrenia. Its Sativex medication, designed to treat cancer pain medication, is in clinical trials.

Follow Strauss on twitter @gbstrauss.