These are companies which do not trade on stock exchanges. It is often difficult to find very much information on these companies, other than a brief directory listing, estimated net sales, and sometimes news articles. These articles can be found by doing a search in various regional newspapers, trade publications and newswires. The newswires which can be very helpful, though are usually only used by and report on larger companies. One can also search Secretary of State Corporate Records or similar for additional information as well as doing a search using any of the wide variety of search engines available. Another place for information are the various types of social media available.