Private (or privately-held) companies are businesses that do not trade shares on a public exchange like the New York Stock Exchange (NYSE).  The Securities and Exchange Commission (SEC) does not require private companies to publicly disclose their financial performance data.

Therefore, finding revenue, profit, sales, etc. for these companies can be difficult.  An excellent resource for researching private companies is PrivCo.  For more on both private and public businesses, consult the Business Library's guide Company Information.