首次公开募股（英语：initial public offerings，缩写：IPO），又名股票市场启动，是公开上市的一种类型。通过证券交易所，公司首次将本应卖给机构投资人的股票转而卖给一般公众（公司从机构投资人那里接收的价格即为首次公开募股的价格）。私人公司通过这个过程会转化为上市公司。首次公开募股通常被公司用来募集资金，尽可能地将早期个人投资者的投资货币化，同时让公司成为公开交易的企业。出售股份的公司没有义务向公众投资者偿还资本。首次公开募股之后，公司的股份会在公开市场上自由交易，资金也仅仅在公众投资者之间流通。尽管首次公开募股可以提供很多有利条件，但是它的缺点也不容忽视。其中最主要的代价就是公募过程中产生的成本，以及在此过程中需要公开某些信息。而这些信息很可能对竞争对手有利，或者给购买者们造成困难。

Initial public offering (IPO) or stock market launch is a type of public offering in which shares of a company usually are sold to institutional investors that in turn, sell to the general public, on a securities exchange, for the first time. Through this process, a privately held company transforms into a public company. Initial public offerings are mostly used by companies to raise the expansion of capital, possibly to monetize the investments of early private investors, and to become publicly traded enterprises. A company selling shares is never required to repay the capital to its public investors. After the IPO, when shares trade freely in the open market, money passes between public investors. Although IPO offers many advantages, there are also significant disadvantages, chief among these are the costs associated with the process and the requirement to disclose certain information that could prove helpful to competitors. The IPO process is colloquially known as going public.