Annual reports (Form 10-K) can be found in a number of Business Library databases, as well as in additional online resources.
According to the Business Reference Services from the Library of Congress:
There are many difficulties in searching for private company information. Consequently, researching private companies often requires considerable creativity. After exhausting some of the more basic directories like Wards, some of the sources below MIGHT reveal more information. One of the most common sources for private companies is Dun & Bradstreet.
Unlike public companies, private companies are not required to file with the Securities and Exchange Commission (SEC) so the information that can be found in those documents is not necessarily available for companies that are private. Many times after a merger (or for other reasons) a company that was once was public chooses, or is forced, to go private. If you want information on those companies, the basic company information will still be available; as well as old SEC documents and the filing to go private (13E-3). You can find additional guidance on researching private companies, in the following publication.
Company web sites
Never underestimate the information that companies publish on their own web sites. However, keep in mind that some companies use their web pages as glorified catalogs, brochures, or advertisements.
Article searches
In addition to searching in business journals, you may also search for articles from multiple sources in many full-text databases.
Local Business Journals
The American City Business Journals are a good source for local company information. Such companies are often the companies that are most difficult to find information on. The site does require registration, and some things are not free, but there is no charge for most access. The site links to business news from over thirty cities including Washington, Seattle, Philadelphia, Birmingham, Baltimore, Albany, Orlando, Nashville, and more.
Secretaries of State
Companies are required to file with the Secretary of State of the state in which they are established. The National Association of Secretaries of State has an easy pull-down menu to find your state's web page.
Use Business Source Premier to locate Industry information.
Select Advanced Search
On the "Select a Field" drop down, choose "IC NAICS CODE OR DESCRIPTION"
Enter the industry's NAICS number
NOTE: Users can limit their Result Lists to "Industry Profiles" from the Source Types filter after conducting a search query, in order to quickly retrieve this type of information source. Also, via the Advanced Search Screen, users can limit searches to Industry Profiles by scrolling down to Publication Type.
For the United States, the main source of industry data is the US Census Bureau, which produces a huge volume of data. It mostly uses the NAICS code to organize the data.
Below are links to the websites for many of the publications from the Census Bureau.
Other data similar to the U.S. Census Bureau