In a Treasury refunding, the amount by which the par value of the securities maturing exceeds that of those sold. 
The state reached when a company or government is repaying more debt than it is... <a target=_blank href='http://www.finance-glossary.com/terms/paydown.htm?id=12874&ginPtrCode=00000&PopupMode=false' title='Read full definition of paydown'>more</a>