A company’s first sale of shares to the public, which brings it onto the stock market.
In an IPO, a company sells new shares and/or existing owners sell theirs to public investors. Investment banks set a price range, collect orders (book-building) and fix the offer price. Afterwards, the stock trades in the secondary market.
First-day jumps are common, but over several years newly listed stocks have, on average, tended to lag the broader market.