Facebook Doesn’t Tell Users Everything it Really Knows About Them
The site shows users how Facebook categorizes them. It doesn’t reveal the data it is buying about their offline lives.
Apparently, tracking everything you do on the web isn't enough… the company also purchases data about your from offline brokers (https://m.facebook.com/help/494750870625830?helpref=uf_permalink.) and it includes your financial information such as total liquid investible assets, estimated household income, etc.