I don't think anyone knows for sure.
I thought I'd read somewhere that it was in their attorney's name or a trust or something like that. I do believe it's public record and I think people were having a hard time finding it at first because it wasn't in an obvious name. Now I've never seen this for myself so I'm not 100% sure.
I was thinking about J&K today (it was a really busy day today too...) and I was wondering how much it costs for their "lifestyle" these days. They have to be making a lot of money from TLC just to "cover" the basics (or TLC's not paying as well and "providing" other things instead). Beyond the house and "basic" bills, unless J or K are doing their own shopping (food, clothing, anything else), someone's doing that for them so there's a cost of someone. I thought I'd read somewhere that Kate has an assistant - again not 100% sure on that. If so, that would be another pay check J&K or TLC would provide. Also the infamous "helper" - someone's paying her I would think. Then the publicist, PR people, lawyer, security. That stuff alone, aside from the "basics" (cost of food, electricty, gas, house, vehicles, car insurance, house insurance, health insuracne, things like that) has got to cost a lot to carry each month. I would think they would have to pay all of the assisants/helpers/staff/whatever a decent amount each month as they've all kept pretty darned quiet to this point so there must be a confidentiality agreement or something in place. Again, just something I was thinking about.