Companies often have a wealth of information on their website. Look for the links to investor relations and/or media contacts.
Reference Solutions
This resource lists companies across the USA. You can use it to identify potential customers, competitors, etc. We don't subscribe, but the Columbia Public Library/Daniel Boone Regional Library does (as do many other public libraries). As an MU student, you are eligible for a library card which will give you access from home. Contact me or the public library if you have questions.