The U.S. Securities and Exchange Commission yesterday proposed a ban on flash trading, a practice that allows certain market participants to access information about the best available prices before the public is given an opportunity to trade. According to SEC Chairman Mary Schapiro, flash orders "provide a momentary head-start in the trading arena that can produce inequities in the markets and create disincentives to display quotes." Public comments on the amendments, which have yet to be published, are being accepted by the SEC until 60 days following their publication in the Federal Register.

Update: The proposed amendments have now been published.