This practice note considers when a prospectus is required under the UK version of the Prospectus Regulation (EU) 2017/1129 and the Financial Services and Markets Act 2000. Focusing on equity securities, it sets out the available exclusions and exemptions from the requirement for a prospectus and also describes when a supplementary prospectus is required. The note contains a table setting out the prospectus requirements for certain corporate transactions including an IPO and various secondary share issues.