House today worth $500,000.
25% equity line = $125,000
Housing reverts the same amount it appreciated 46%.
$500,000 - $270,000 = $230,000 new value
$230,000 - $125,000 = $105,000
$105,000 - costs of defaulting = risk or loss
$125,000 IOU / $270,000 loss = 46%
Problem is...