In the USA private companies are not required by law to release any information to the public so researching them can be very difficult. If the company was a startup try using Pitchbook.
Fame |
UK - Includes all UK registered companies. Note that small companies have different filing requirements. |
Orbis |
Europe -.Our coverage is for companies wiht an operating revenue >= $13 million US (10 million EUR) or over 150 emplyees. |
Capital IQ |
Global - Covers some private companies, particularly good at Private Equity backed companies. Use S&P capital IQ pro (registration required) to thoroughly check private company coverage as this has better coverage. |
Mergent Online |
Global - Ensure you tick the box for private companies. Some limited data may be available from D&B. |
Factiva |
Global - use the Companies and Markets tab > Company to see if there are any figures for a private company. |
Proquest |
Global - search for the company by name and use the side bar to limit by date and to publication titles to private company research reports. |
Pitchbook
Go to single sign on |
Global - a database for PE/VC - and is useful to find VC funded (private) companies. Minimal downloading is availble so you must do your analysis in the product. |
Forbes provides a list of America's largest private companies.
The Library of Congress adivises on sources of data and the issues when researching US companies here.
Public Disclosure Requirements for Private Companies: U.S. vs. Europe.