Such disclosures must take place simultaneously in the case of a deliberate disclosure of information. The unintentional disclosure of such information must be immediately disclosed to the public. Disk Regulation Regulation (Reg FD) is a rule adopted by the Securities and Exchange Commission to prevent selective disclosure by listed companies to market professionals and certain shareholders. In December 1999, the SEC proposed the FD Regulation. Thousands of individual investors have written to the SEC to express their support for the regulation. But the support was not unanimous. Large institutional investors, accustomed to benefiting from selectively disclosed essential information, fought vigorously against the proposed regulation. They argued that fair disclosure would result in less disclosure. In October 2000, the SEC announced the FD Regulation.