A more thorough explanation:

Post-effective period refers to the stage in the process of an initial public offering (IPO) after the Securities and Exchange Commission (SEC) has declared the issuer's registration statement effective. During this period, the issuer must comply with Section 5 of the Securities Act and SEC regulations, which govern the issuer's communications and activities throughout the IPO process.

The main requirement for issuers during the post-effective period is to deliver the prospectus to investors. The prospectus is a legal document that provides information about the company, its financials, and the risks associated with investing in its securities. By delivering the prospectus, the issuer is providing investors with the information they need to make an informed investment decision.

For example, if a company XYZ has just completed its IPO and the SEC has declared its registration statement effective, XYZ must deliver the prospectus to investors during the post-effective period. This will allow investors to review the information provided in the prospectus and decide whether or not to invest in XYZ's securities.

Another example could be a company ABC that is planning to go public. During the post-effective period, ABC must comply with Section 5 of the Securities Act and SEC regulations, which means that it cannot engage in any activities that could be considered gun jumping. This includes making any public statements about the offering or soliciting investors before the registration statement becomes effective.