In general, it is harder to find information--and the information available tends to be more limited--for private companies as opposed to public ones.
In addition to not reporting finances, private companies may be more closed-mouthed about operations, planning, personnel, and other strategic moves. Also, because they are not publicly traded, stock and investment analysts do not generally research and write about these companies in great detail.
NEW: CB Insights (link below) is a database that focuses on private companies. Although it does its own research and compiles information from a variety of sources, you still can't expect to find the level of accurate, verifiable, and detailed information that is available for public companies.
TIP: Look for SWOT (Strength, Weaknesses, Opportunities, Threats), bank / brokerage / independent analysts' reports, and more in the following databases:
NEW!
This link opens in a new window This link opens in a new windowProvides data, statistics, insights, and perspectives for marketing in a digital world.
This link opens in a new windowOriginal market research on product categories, consumer groups, and general trends. Mostly US and Europe-focused.
This link opens in a new windowProvides international market intelligence, including economic statistics, on industries, countries, and consumers.
Many of the databases listed above have basic stock price information including historical comparisons.
For financial information directly from a company, look for its annual report (the formal "pretty" or designed version that includes the required financial disclosures along with other info) or the 10K report (or 10Q quarterly reports) filed directly with the SEC (U.S. Securities and Exchange Commission) using EDGAR.
If a company is public but not traded on a U.S. exchange (or if less than 50% of the shares are) they may file a 20F report,
Search for a company's "investor relations' page or use some of the sites below to see info online and/or order paper copies.