This guide is designed to give someone searching for company information a place to start with a few ideas and strategies for finding company information. The content of this guide is not intended to include all sources of company information, in all places, or published by all publishers—there are too many sources than could be included in a single guide. While the bulk of this guide is focused on more common sources that may be of use for those looking for information on companies that are in the U.S. and active, and for those looking for current information - there is a section for international companies and many of the sources can also be used for historical research.
It is important to note, that each research project will be different and have different constraints so the sources and strategies included here are just to get someone started.
When doing company research there are many sources to use. Depending on the company—its size, industry, or location—some sources will be good while others will not. Small and private companies tend to be harder to research; researching them tends to be a more creative exercise. Those companies in industries that are dominated by private companies or those in areas that are more suspicious of their competitors, also tend to keep their information more closely held and also can require creative searching. While you will find a lot of information available on the Internet, it may not be reliable, and you may not find what you are looking for if you rely solely on free Internet sources.
Finally, many of the best sources included here may be available in a local public or university library so check to see what you have access to locally.