SEC boss Mary Schapiro is now speaking out in support of the little guy.

The head of the Securities and Exchange Commission told Congress yesterday that enforcement agents are studying whether small investors were victims of any illegal profiteering during the chaos of the May 6 stock-market plunge.

“I am deeply concerned about the effects that this volatile market had on investors, especially retail investors whose trading orders may not have behaved as they were intended or who otherwise may have been unfairly harmed,” Schapiro said during a Senate Banking subcommittee hearing.

“If we identify any activity that violates the securities laws, we will take appropriate action,” she warned.

The remarks suggest the effort to track and review the intraday crash — which saw the Dow Jones industrial average sink by nearly 1,000 points in a matter of minutes — continues to expand.

Schapiro has led efforts to work with the nation’s exchanges as well as the Commodities Futures Trading Commission to get to the bottom of the collapse.

Although markets largely recovered just as suddenly as they plunged that day, regulators and officials at stock exchanges have yet to identify exactly what prompted the Dow to take its breathtaking fall. The speculation has centered on computer-driven high-speed trades that spiraled out of control.