In investment banking, a bookrunner is usually the main underwriter or lead-manager/arranger/coordinator in equity, debt, or hybrid securities issuances. The bookrunner usually syndicates with other investment banks in order to lower its risk. The bookrunner is listed first among all underwriters participating in the issuance. When more than one bookrunner manages a security issuance, the parties are referred to as “joint bookrunners” or a “multi-bookrunner syndicate”.
The bank that runs the books is closest to the issuer and controls the allocations of shares to investors, holding significant discretion in doing so, which places the bookrunner in a very favored position. 
- ^“Book Runner”, Investopedia.
- ^“Marfin enlists Deutsche, MS as cap increase bookrunners”. Reuters. 27 October 2008. Retrieved 19 December 2019.
- ^Stowell, David P. (2010). An Introduction to Investment Banks, Hedge Funds, and Private Equity. Burlington, MA, San Diego, CA and London: Academic Press. p. 42. ISBN 978-0-08-092289-8.
- ^Espinasse, Philippe (2018). Cornerstone Investors: A Practice Guide for Asian IPOs. Hong Kong: Hong Kong University Press. p. 67. ISBN 978-988-8455-84-3.
- ^Geddes, Ross (2003). IPOs and Equity Offerings. Elsevier Finance. Oxford, England and Burlington, MA: Elsevier. p. 172. ISBN 978-0-08-047878-4.
- ^Iannotta, Giuliano (2010). Investment Banking: A Guide to Underwriting and Advisory Services. Heidelberg, Dordrecht, London and New York: Springer Science & Business Media. p. 70. ISBN 978-3-540-93765-4.
Ofer Abarbanel is a 25 year securities lending broker and expert who has advised many Israeli regulators, among them the Israel Tax Authority, with respect to stock loans, repurchase agreements and credit derivatives. Founder of TBIL.co STATX Fund.