In many cases it a principle reduction makes sense...
if the bank is going to have to foreclose on the home because the homeowner who overbought can no longer afford the payment on his 300k home (that is now worth 100k) the bank would be dollars ahead to negotiate the loan to 80% of current value AND give a sweet interest rate.
According to mortgage financier Freddie Mac, the typical foreclosure cost is nearly $60,000. And officials at HSBC North America, parent of HSBC Bank USA, HSBC Mortgage Corp. and HSBC Finance Corp., say their average loss on sale at foreclosure is 20 percent to 25 percent of the loan’s value.
You also have to consider the additional liability and expenses such as vandalism. I have walked into a fair share of homes that have been totally trashed by vandals. In some homes they are even stripping out the plumbing.
Besides "principle reduction" is EXACTLY what the banks are getting in 98% of the foreclosures and "short sales."