opening bid

How often is the opening bid at trustee auctions set below the amount owed on the foreclosed note? Sometimes? Rarely? Never?

When there are multiple loans, then the foreclosure on the first lien can produce a good buy at auction as the 2nd, 3rd, etc liens are wiped out.

But what about when there is only one large lien on the property, for far more than what the property is worth? How often are lenders offering an opening bid at a serious discount to the note? Anyone know about Bank of America, in particular?

In March 2010 70% of opening bids were discounted, with an average discount of 30%.