A private company becomes a public company in a process called an initial public offering (IPO). Historically, only private companies with a strong track record of years of growth have considered themselves ready to take this significant step. The IPO has pros and cons that include exchanging a host of high regulatory costs for the benefits of significant capital. After a company "IPOs" or "goes public," investors and the general public can buy stock, and existing shareholders can sell their stock far more easily than when the company was private.
Companies take years to IPO after being formed. The median time between a company’s founding and its IPO has been increasing. According to a Harvard report, companies that went public in 2016 took 7.7 years to do so, compared to 3.1 years for companies that went public in 1996.