Shelf prospectus: filing and updated information memorandum required, Board observation governs offer window and web disclosure. Issuers that are public sector banks, scheduled commercial banks or public financial institutions must file a draft shelf prospectus with the Board (excluding fast track issues), follow Chapter V processing, disclose the aggregate amount to be raised, and obtain an observation letter of fixed validity. For each subsequent stage issuers must file an updated information memorandum/shelf prospectus with the Board and Registrar, and upload the updated shelf prospectus on the Board's and lead manager's websites before opening that stage.