I'm not an expert here, and I'd have to go read the law in detail to know for sure, but my limited experience leads me to believe that it likely does apply to p

I'm not an expert here, and I'd have to go read the law in detail to know for sure, but my limited experience leads me to believe that it likely does apply to private companies in the course of business in some cases. If the company is a federal contractor, for instance, there are a slew of federal regulations with which they must comply to remain eligible for contracts. Likewise, government grants come with strings attached as well. Finally, if the behavior that you're investigating is illegal - such as discrimination against a "protected class" - there's always the possibility of suing them and acquiring the documents through discovery. All it takes is money.