That data is essentially sourced from clearbit afaik.
I'm really interested in who is selling it; I've been puzzling over this for a while. Lots of companies have high accuracy employer to IP address data like that -- think GSuite, Office 365, etc -- but who on earth has an incentive to sell it? In the case of GSuite, google keeps data like that for itself. For Office365, the value of the data pales next to the $100/year/user they charge.
One guess is maybe the Adobe suite? Still, I kind of think this would be too sleazy for them.
Let me walk back that "too sleazy for Adobe" -- too sleazy for my guess for the $ on offer. The money probably is not large; maybe low to mid 6 figures tops. That type of money probably can't even get you a callback from a BD person at Adobe; they don't get out of bed for under a million dollars.
Considering clearbit started at a time when there was not so much focus on privacy and customer data protections... I’m gonna take a wild guess here and say they are scraping it from publicly available (ish) sources.
That is discounting the obvious possibility of looking at ARIN allocations, where in some cases the IP address might be registered to an ASN belonging to the company. In that case it’s a simple lookup.
I'm really interested in who is selling it; I've been puzzling over this for a while. Lots of companies have high accuracy employer to IP address data like that -- think GSuite, Office 365, etc -- but who on earth has an incentive to sell it? In the case of GSuite, google keeps data like that for itself. For Office365, the value of the data pales next to the $100/year/user they charge.
One guess is maybe the Adobe suite? Still, I kind of think this would be too sleazy for them.