Private companies do not have stock that is widely traded on stock exchanges. As such they are not required to file financial statements with the Securities and Exchange Commission (SEC). Private companies come in all sizes and industries and can even include subsidiaries of a publicly traded company.
Finding information about private companies is more time consuming and difficult since the primary source of information tends to be news stories. However, even news stories tend to provide less detailed information than what is easily available for public companies. In addition to using resources listed throughout this guide try these resources in your search for private company information.
"All 50 states make some level of corporate and business filings available online. In a few instances only limited information (such as name availability) is retrievable. The majority of the states, however, use their Web presence to disseminate a range of public business records -- and most of them offer access at no charge."