Securities and Exchange Commission chairman Mary Schapiro said Wednesday she is worried about the role of high-frequency traders in the stock market and hinted at new policies aimed at curbing frenetic market activity.

A large portion of trading in the equities market has little to do with "the fundamentals of the company that's being traded" and more to do with "the minuscule aberrational price move" that computer-assisted traders with direct connections to the exchange can "jump on" in fractions of a second, Schapiro said.