As mentioned by ih37, the biggest difference between a public company and private company is that you could buy shares of the public company and the company is required to file quarterly earnings reports with Securities and Exchange Commission. This gives public companies advantage to raise capital to expand the business by selling stocks and bonds. The main advantage of private companies is that management doesn’t have to answer to stockholders and isn’t required to file disclosure statements with the SEC. Public companies must inform shareholders about and get approval for the company’s operations, financial performance, management actions, and other decisions. Some of the top public companies are: Apple, Berkshire Hathaway, JPMorgan Chase, ExxonMobil, AT&T, Bank of America, Wells Fargo, Verizon, Microsoft and Wal-Mart.