A first mortgage with very little deposit plus a second or even third mortgage followed by a sharp fall in price and it’s quite easy to imagine someone owing more than 200% of what a home is worse. The mind boggles at the lack of foresight from both the borrower and the banks but it’s certainly believable.

I agree about the hues being too close and I found that in “busy” areas the rollover doesn’t work correctly so some counties are never accessible. On a broader level, while this is an interesting and potentially useful graphic, it is only as good as what underlies it and based on the absolutely bizarre valuations Zillow puts on things in my local area I wouldn’t have much faith in this.

I think the issue is how you compute percentage. If Mortgage = M and current Value = V, and M > V, then (M – V)/V can easily be over 2.00. But (M-V)/M could never be greater than 1.0. So, the question is percent of mortgage, or percent of current value.