(15)Article 20 of Regulation (EU) 2017/1129 contains deadlines for a competent authority to notify the issuer, the offeror or the person asking for admission to trading on a regulated market about its decision regarding the approval of the prospectus, and measures to address situations where that competent authority fails to meet those deadlines. The scrutiny and approval of prospectuses is, however, an iterative process and the decision of the competent authority to approve the draft prospectus may involve several rounds of analyses of the draft prospectus by that competent authority and ensuing implementation of improvements by the issuer, offeror or person asking for admission to trading on a regulated market. It is therefore also necessary to enable a competent authority to set out deadlines for the issuer, offeror or person asking for admission to trading on a regulated market by which they should submit, where required by that competent authority, supplementary information or a revised draft prospectus. Additionally, it is necessary to set out the maximum overall timeframe from the receipt of the initial application for approval of a draft prospectus to the decision to either approve or not approve that prospectus and terminate the review process, as well as the conditions for possible derogations from that timeframe.