They’ve got high hopes.

Bruce Perlowin, the chief executive officer of Hemp Inc. who has seen his stock soar 205 percent to 8 cents in the last three days, says investors are suddenly bidding up marijuana companies because they want to find “the next Microsoft.” Robert Frichtel, his Advanced Cannabis Solutions Inc. up 144 percent after posting $455 in sales last quarter, said “euphoria” is driving gains that in some cases top 1,700 percent.

“The demand for marijuana is insatiable,” said Perlowin, a once-jailed smuggler who filed last month to sell 12 million shares of the Las Vegas-based company even as its market value holds 99.97 percent below the world’s biggest software maker. “You have a feeding frenzy for the birth of a new industry.”

While regulators warn of scams, some of the biggest percentage gains in the stock market this year are being harvested by investors speculating on marijuana penny stocks. GreenGro Technologies Inc., which provides management services for medical dispensaries, has soared 1,714 percent to 80 cents. Tranzbyte Corp., which sells pot in Colorado, has gained more than 310 percent in five trading sessions, crossing above a penny for the first time in 11 months.

Frenzy is afoot after Colorado became the first state to legalize sales to anyone 21 and older and New York considered reviving a law to allow some hospitals to use the drug for patients with cancer, glaucoma and other illnesses. Among 10 marijuana-related stocks that have rallied more than 20 percent this year, most are priced below $1 and trade over the counter.

“It’s people freaking out, thinking they found the next home run and doing no research,” Frank Ingarra, head trader at Greenwich, Connecticut-based NorthCoast Asset Management LLC, said by phone. “There might be one or two that survive, but having seen crazes like this, people have been burned by them a lot. The average investor should think twice.”

The Financial Industry Regulatory Authority issued an alert in August saying investors should beware of potentially fraudulent purveyors of stocks connected to pot and related services. Scammers may be promoting the shares, then selling them in what’s called a “pump-and-dump” scheme, the brokerage watchdog organization said in an e-mailed statement. It didn’t name any companies.

Finra Warning

Investors should be particularly wary of executives who have been incarcerated, according to Finra’s alert, which mentioned an unnamed CEO who spent nine years in prison for running one of the largest drug-smuggling operations in history. Perlowin of Hemp Inc. said in an August interview that he thought the group meant him and that it’s “absurd” to criticize him for his experience dealing marijuana.

Hemp Inc. focuses on industrial hemp used in clothing and camping gear, Perlowin noted.

“I don’t really know that there’s a lot of stock-market money to be made in this,” Brian Barish, president of Denver- based Cambiar Investors LLC, which manages $9 billion, said in a telephone interview. “I’ve definitely seem some interest and gotten a couple calls. Most of them have been with chuckles on the other end of the line.”

Eighteen states and Washington, D.C., allow the medical use of marijuana and 11 permit sales through dispensaries, according to the Denver-based National Conference of State Legislatures. National legalization has the potential to start a $35 billion to $45 billion a year industry, according to Bloomberg Industries.

Pot for recreational use sells for an average of $400 an ounce, compared with $200 an ounce that Colorado retailers collect for medical marijuana, according to Aaron Smith, executive director of the National Cannabis Industry Association, a Washington-based trade group.

Building Momentum

Medbox Inc., which has a market value of $920 million, climbed to a one-year high of $73.90 on Jan. 7. The West Hollywood, California-based company had about $260,000 in profit on sales of $2.1 million in the third quarter of 2013, according to a Nov. 19 statement.