If it is a public company, go to the annual report to shareholders. The annual report is perhaps the best single source of information on a company, but keep in mind that it is written partially as a promotional tool by the company itself and is not an entirely unbiased source. Annual reports appear as parts of various database services, and many companies provide annual reports on their websites or will send out paper copies on request. When you are on a company’s website, look for a link labeled Investor Relations.
Private companies are not required to file annual reports, although some will publish reports as a promotional tool. These private company annual reports are virtually impossible to obtain except from the company itself, and all information in such a report must be treated cautiously. Business directories provide basic information on private companies, such as number of employees and annual sales estimates. Lastly, search local or regional newspapers for information on local and private companies.