Private companies in the US are not obligated to file with SEC and therefore, limited information is available for such companies. Some providers such as those listed below include brief financial information that they either hand-collect or aggregate from other sources. Be careful when using this data as it could be inaccurate or outdated.
Capital IQ
D&B Hoovers
Orbis
All of the above databases are listed in the Companies guide.
Bloomberg. Type PSCR [GO] to search hundreds of thousands of private companies and subsidiaries worldwide. Screen by location, industry, size, and private equity backing.
Financials for subsidiaries are filed with the parent company.