Michael Lewis has an argument whether high-frequency trading has rigged the stock market and changes in equity trading need to be made, said Pacific Investment Management Co.’s Bill Gross.

“High-frequency trading as applied to the stock market has a negative cast,” Gross said in an interview on Bloomberg Radio with Tom Keene. “Michael Lewis has an argument. I won’t necessarily use his words because they’ve gotten him into hot water.”

Gross, who oversees the $232 billion Total Return Fund, said investors should call their brokers and ask how trades are being handled. Scrutiny of high-frequency trading is intensifying after this week’s publication of Lewis’s book, “Flash Boys.” The practice involves software-driven strategies that usually employ super-fast computers to post and cancel orders at rates measured in thousandths or even millionths of a second.

Lewis said the stock market is rigged when high-frequency traders with advanced computers make tens of billions of dollars by jumping in front of investors. Everyone who owns equities is victimized by the practice, in which the fastest traders figure out which stocks investors plan to buy, purchase them first and sell them back at a higher price, says Lewis, a columnist for Bloomberg View.

Mario Gabelli, the founder of Rye, New York-based Gamco Investors Inc., said in a separate interview on Bloomberg Television that flash trading is a rip-off of consumers.

Bid Disappears

“If you go in and watch the stock and how they probe at $60.22 a bid for 400 shares, before you can put in an order to sell it, the bid disappears,” Gabelli said. “They should hold it firm for a period of time.”

While Lewis sees exploitation rampant among the more than 50 public and private venues that make up the American stock market, his thesis has drawn rebuttals from executives such as Bill O’Brien, the president of exchange operator Bats Global Markets Inc.

The Securities and Exchange Commission is investigating high-frequency and automated trading, Chairwoman Mary Jo White told lawmakers April 1. The Federal Bureau of Investigation is soliciting traders and stock-exchange workers to blow the whistle on possible front-running and manipulation via high-speed computers.