Private companies are not required to file public financial statements. Usually only revenues will be reported in directories and other sources. If you're lucky: some companies may submit unaudited data to credit rating organizations such as D&B, but these are available from D&B for a fee. Larger companies may be preparing for an initial public offering (IPO) on a US stock exchange which requires filings with the SEC.
Try the following sources:
Check the following for information: