When looking for information about a company, consider both information from the company itself (For example the company website or press releases) as well as information about the company written by others (Explore the Articles and News tab). For private companies, literature searches, company blogs, and interviews may be some of the best and only resources for locating information.
Information on private companies can be sparse. Private companies are not required to file any financial data in the U.S., with the exception of registration data filed with the Secretary of State, in the state where they are registered. Databases like Mergent Intellect, Data Axle, Orbis and PrivCo have some basic data on U.S. private companies. Often 'local press' have more stories on locally based companies than national newspapers.