IPOs usually contain lock-up provisions that forbid investors (such as corporate officers and directors, or investors such as venture capitalists who own large amounts of the newly public firms’ shares) from selling their shares until a certain time after the IPO. By law, insiders must retain their shares for 90 days after the IPO, although some prospectuses required them to hold the shares even longer. The main reason for the lockup provision is to prevent insiders from selling what may turn out to be overpriced stock immediately after the offering. Insiders can sell their shares as part of the IPO, but his information must be disclosed in the prospectus. Such selling typically is discouraged by the investment bank, however, as insider selling at the IPO sends a bad signal to the market about the insiders’ optimism for the firm’s future.