Private companies are those for which there is no public ownership of its shares or assets.
In the United States, the majority of businesses are privately held. Because private companies are not required to file with the Securities and Exchange Commission (SEC) the information sources for private company research are reduced considerably.
Consequently, researching a private company may require considerable creativity and persistence. After consulting some of the basic directories like ReferenceUSA Business and Corporate Affiliations some of the sources in this guide may include more substantive information.