Answer

Companies provide access to basic information on their websites or in their SEC filings if they are a public company, see SEC.gov.  Information can generally be found under the Investor Relations tab of the company website. 

Go to the Business Library's Company & Financial Information section for links to useful resources including links to the following suggested resources. Many of the resources can be used for both U.S. and international companies as well as public and private companies.

Business Insights: Essentials:  Go to the Companies tab and search for a company. Data provided includes a company chronology, histories, rankings, and multiple other data items. 

Hoover's: Data provided includes an overview, stock data, competitors, industry information, people and other data items. 

ReferenceUSA: Choose U.S. Businesses.  Both closed and current businesses are included. Use the Corporate Tree item if you are unsure of which company is the parent company. Under the Quick Links go to data item, Profile, or any of the other data items such as business history, business demographics, news and more.