First or initial public offer is the first sale of stock by a private company to the public. In an IPO, the issuer may obtain the assistance of an underwriting firm, investment bank, which helps it determine what type of security to issue (common or preferred), best offering price and time to bring it to market. An important part is the preparation of documentation with the most important information on the company, prospectus and doing all the legislative work concerning registration with the competent state authority. A large IPO is usually underwritten by a syndicate of investment banks led by one or more major investment banks (lead underwriter). Usually, the offering will include the issuance of new shares, intended to raise new capital, as well the secondary sale of existing shares. Initial public offering is most often used as an instrument of privatization of big publicly owned companies or with private companies where existing owners want to ensure fresh capital needed for company development in the most transparent way.