US securities regulators are reviewing whether to ease limits on what companies can say ahead of initial public offerings, after lawmakers complained small investors were kept in the dark during this year's botched stock sale by Facebook.

Mary Schapiro, chairman of the Securities and Exchange Commission, has asked her staff to review the "quiet period" rules barring remarks about a firm's prospects around the time of a share sale, according to a letter she recently sent to Rep. Darrell Issa (R., Calif.).