Bookrunner: A term used in the investment and finance industry, a bookrunner is the lead underwriter or manager for a particular securities offering. This person or organization is responsible for coordinating the process of marketing and selling the security to investors. They are typically an investment bank or broker-dealer with expertise in issuer related services such as managing the pricing of an issue, allocating the shares to different investors and handling post-trade settlement of transactions. In short, they are the “runners” of the investment book.