NEW YORK — The nation’s top securities regulator halted the buying and selling of 255 stocks in what the agency called a “massive trading suspension” to curtail a persistent investor fraud.

The U.S. Securities and Exchange Commission said Monday the suspensions — part of its “Operation Shell-Expel” — affects stocks of dormant companies based in 26 states and two foreign countries.

The action is part of a broader crackdown on fraud involving shares of small, or “micro-cap,” companies. The SEC’s worry is that the low-priced or “penny” stocks are ripe for abuse by fraudsters in so-called pump-and-dump schemes — akin to the massive fraud highlighted in Martin Scorsese’s latest film “The Wolf of Wall Street.”

In such scams, fraudsters artificially inflate the prices of shares of apparently inactive companies, then profit big by selling the stocks after they increase in value. The stocks in question are not traded on established exchanges but are bought and sold over the counter.

“A frequent element in pump-and-dump schemes has been the use of dormant shells,” Andrew Ceresney, the SEC’s enforcement director, said in a statement.

The SEC’s action highlights the continuing threat penny stock frauds pose to investors, long since the day of Jordan Belfort, whose 1990s scheme was brought to life in “The Wolf of Wall Street.”

Belfort’s company was called Stratton Oakmont. It was a Long Island, N.Y.-based brokerage that hyped penny stocks to unsuspecting investors largely using telephone calls.

The penny stock fraudsters of today, however, no longer need scores of brokers all in one room. They can span the globe and use the Internet to lure investors via email or post phony company financial statements online.

“The higher degree of technology has made it far easier for them to pull off these frauds,” Doug Leff, assistant special agent in charge of white-collar criminal investigations at the FBI’s office in New York, said in a recent interview. “It’s fair to say from the time of Belfort’s fraud that these things have evolved both in sophistication and in quantity.”