Private companies are companies that are not publicly traded on an exchange market such as the New York Stock Exchange. They are typically owned by the founders of the company, current management or a private equity group.
Private companies have some advantages over public companies. They are not required to file quarterly and annual earnings reports, and they don't have to disclose their financial information to the public. Additionally, private companies aren't required to follow generally accepted accounting principles or the Sarbanes-Oxley Act. Most private companies are small businesses, but some large private companies are included in the Fortune 500 list.