Delisting refers to the practice of removing the stock of a company from a stock exchange so that investors can no longer trae shares of the stock on that exchange. This typically occurs when a company goes out of business, declares bankruptcy, no longer satisfies the listing rules of stock exchange, or has become a private company after a merger or acquisition. In the United States, securities which have been delisted from a major exchange may be traded on over-the-counter markets like the OTC Bulletin Board or the Pink Sheets.