The sale of equity shares or other financial instruments by an organization to the public in order to raise funds for business expansion and investment. Public offerings of corporate securities in the U.S. must be registered with and approved by the SEC and are normally conducted by an investment underwriter.

Generally, any sale of securities to more than 35 people is deemed to be a public offering, and thus requires the filing of registration statements with the appropriate regulatory authorities. The offering price is predetermined and established by the issuing company and the investment bankers handling the transaction. The term public offering is equally applicable to a company's initial public offering, as well as subsequent offerings.