The National Association of Securities Dealers (NASD) was a self-regulatory organization in the United States that oversaw the securities industry. Established in 1939, its primary role was to create and enforce rules for brokerage firms and their registered representatives, ensuring fair and ethical practices in the trading of securities. In 2007, the NASD merged with the New York Stock Exchange (NYSE) to form the Financial Industry Regulatory Authority (FINRA). This merger aimed to enhance regulatory oversight and improve investor protection in the financial markets, continuing the legacy of the NASD's commitment to maintaining market integrity.