Revenue Databases

[James Boston]

I am vaguely familiar with something that I would like to know more about.

I beleive there are figure published, available for purchase, that provide databases of privately owned businesses in a particular area. One of the "filters" you can put on these databases is business revenue.

1) Did I dream this, or does such a thing exist?
2) How are privately owned businesses' revenue made available like that?
3) Any idea where this information is found?