Ask HN: This company links my home IP address to my employer. How?

I've just had a spooky experience at http://wowanalytics.co.uk/ - I work remotely and was researching WOW Analytics website for a client. They have some buzzwordy technology that links IP addresses to companies.

Fair enough I thought... until they linked my home IP address to my company. Yes I'm a director of it but no domains point to my home IP address, this postal address etc...

So how the heck did they manage that? Short of having filled in a form on a website with the company name, and it saving name + IP address, I can't think how it could make that leap...