The Securities and Exchange Commission has begun plotting how to curb abuses in high-frequency trading, as part of its broader effort to ensure that market regulations keep pace with trading realities.
HFT, as it is commonly called, now accounts for roughly two-thirds of trading volume in the equities markets. It is also a prime suspect in the “flash crash” that sent hundreds of stocks seesawing for 5 minutes on the afternoon of May 6—an event that deeply spooked investors and regulators alike.
