(49)Article 21(1) of Regulation (EU) 2017/1129 requires, for an IPO to the public of a class of shares that is admitted to trading on a regulated market for the first time, the publication of a prospectus at least six working days before the end of the offer. In order to foster swift book-building processes, especially in fast moving markets, and to increase the attractiveness of the inclusion of retail investors in such offers, the current minimum period of six days between the publication of the prospectus and the end of an offer of shares should be reduced, without affecting investor protection.