Initial public offering

An initial public offering (IPO) or stock launch is a public offering in which shares of a company are sold to institutional investors and usually also to retail (individual) investors. An IPO is typically underwritten by one or more investment banks, who also arrange for the shares to be listed on one or more stock exchanges. Through this process, colloquially known as floating, or going public, a privately held company is transformed into a public company. Initial public offerings can be used to raise new equity capital for companies, to monetize the investments of private shareholders such as company founders or private equity investors, and to enable easy trading of existing holdings or future capital raising by becoming publicly traded.

After the IPO, shares are traded freely in the open market at what is known as the free float. Stock exchanges stipulate a minimum free float both in absolute terms (the total value as determined by the share price multiplied by the number of shares sold to the public) and as a proportion of the total share capital (i.e., the number of shares sold to the public divided by the total shares outstanding). Although IPO offers many benefits, there are also significant costs involved, chiefly those associated with the process such as banking and legal fees, and the ongoing requirement to disclose important and sometimes sensitive information.

Details of the proposed offering are disclosed to potential purchasers in the form of a lengthy document known as a prospectus. Most companies undertake an IPO with the assistance of an investment banking firm acting in the capacity of an underwriter. Underwriters provide several services, including help with correctly assessing the value of shares (share price) and establishing a public market for shares (initial sale). Alternative methods such as the Dutch auction have also been explored and applied for several IPOs.

The earliest form of a company which issued public shares was the case of the publicani during the Roman Republic, although this claim is not shared by all modern scholars. Like modern joint-stock companies, the publicani were legal bodies independent of their members whose ownership was divided into shares, or parts. There is evidence that these shares were sold to public investors and traded in a type of over-the-counter market in the Forum, near the Temple of Castor and Pollux. The shares fluctuated in value, encouraging the activity of speculators, or quaestors. Mere evidence remains of the prices for which parts were sold, the nature of initial public offerings, or a description of stock market behavior. Publicani lost favor with the fall of the Republic and the rise of the Empire.

In the United States, the first IPO was the public offering of Bank of North America around 1783.

When a company becomes publicly listed, the money paid by the investing public for the newly issued shares goes directly to the company (primary offering) as well as to any early private investors who opt to sell all or a portion of their holdings (secondary offerings) as part of the larger IPO. An IPO, therefore, allows a company to tap into a wide pool of potential investors to provide itself with capital for future growth, repayment of the debt, or working capital. A company selling common shares is never required to repay the capital to its public investors. Those investors must endure the unpredictable nature of the open market to price and trade their shares. After the IPO, when shares are traded in the market, money passes between public investors. For early private investors who choose to sell shares as part of the IPO process, the IPO represents an opportunity to monetize their investment. After the IPO, once shares are traded in the open market, investors holding large blocks of shares can either sell those shares piecemeal in the open market or sell a large block of shares directly to the public, at a fixed price, through a secondary market offering. This type of offering is not dilutive since no new shares are being created. Stock prices can change dramatically during a company's first days in the public market.

Once a company is listed, it is able to issue additional common shares in a number of different ways, one of which is the follow-on offering. This method provides capital for various corporate purposes through the issuance of equity (see stock dilution) without incurring any debt. This ability to quickly raise potentially large amounts of capital from the marketplace is a key reason many companies seek to go public.

An IPO accords several benefits to the previously private company: