An initial public offering (IPO) is the process by which a private company first sells shares to the public and lists on a stock exchange, raising capital and becoming subject to public-company disclosure requirements.
A company works with underwriting banks to set an initial share price and offer size, then lists on an exchange — at that point its shares become freely tradable by the public rather than held privately by founders, employees, and venture investors. The company gains access to public capital markets and also takes on new obligations: quarterly and annual SEC filings, public earnings calls, and broader shareholder scrutiny.
The market has limited historical data to anchor a fair price on, so early trading tends to swing more sharply in both directions than an established stock with years of price history.
A contractual window (commonly 90-180 days) after an IPO during which company insiders and early investors are restricted from selling their shares — its expiration can add a temporary wave of selling pressure.
Browse all S&P 500 tickers to see this metric applied to individual companies.
Educational research only — not investment advice.