Business Writing 3016: Company Research
A private company is held by a handful of people, often the founder and a few others. It does not sell stock to the general public, and therefore, does not have an obligation to disclose its financial information. Finding financial information on a private company can sometimes be difficult.
A public company, on the other hand, has sold a part of its business or its stock to the general public. By law it is required to disclose its financial information and file specific reports with the U.S. Securities and Exchange Commission (SEC).
If you are not sure if a company is public or private, check these sources.