If a borrower defaults on a mortgage, the lender can start foreclosure proceedings. The party pursuing the foreclosure—whether this is the original lender or not—must produce the mortgage note. Some foreclosures have been defeated because the mortgage note could not be produced. However, the Uniform Commercial Code (UCC), a set of business laws that regulate financial contracts employed across states, does in fact allow foreclosures in case of lost notes, according to Joseph William Singer, a law professor at Harvard University.