Mortgage Q&A: Tight credit Fed's prime challenge

"Even if the Fed maintains its policy of keeping the federal funds rate at 0.25 percent, it does not guarantee that mortgage rates will remain low. In fact, the Fed has stated that it will complete its mortgage-debt purchase program in early 2010. The simple law of supply and demand tells me that rates are likely to rise when this happens because demand for mortgage-backed securities will fall sharply."