Private companies are those for which there is no public ownership of their shares or assets. Because private or family-owned companies are not required to file detailed financial information with the Securities and Exchange Commission (SEC), there are a lot fewer information sources for private company research. Public companies are those that are listed on at least one public stock exchange (such as NYSE and NASDAQ) and have issued securities for ownership in the company to public investors.
Here are some general guidelines for searching for information on non-public companies:
Search for the Company/Organization's name when searching online for news and journal articles.
Search the Industry of the company/organization to find out news, trends, threats, etc. Think about how the company compares to others in the industry. What is going on in the industry of your company (e.g. pricing trends, competition, cost trends, innovation) and also what is happening in the operating environment (e.g. economy, demographic trends, regulation/laws, etc.
Search the Organization/Company’s website for any information they may have available to the public such as press releases and news. However, be sure to understand the bias of information posted on a company's website. They are not likely to post negative information.
Scroll to the “Companies” category to see lists of companies, most of which have at least $1 billion in annual revenues and either too few shareholders to be required to file financial statements with the Securities & Exchange Commission or shares whose ownership is restricted to some group, like family members or employees.
Since 1996, Red Herring has complied a list of the top 100 private technology companies. The site includes the top 100 companies in the Global, North American, Europe and Asia categories. To be included on the list companies must be technology or life science-based and privately held.