Others have emphasized the subdued overall business demand for credit in the United States and the apparent eagerness of lenders, including foreign investors, to provide financing. In particular, heavy purchases of longer-term Treasury securities by foreign central banks have often been cited as a factor boosting bond prices and pulling down longer-term yields.
Thirty-year fixed-rate mortgage rates have dropped to a level only a little higher than the record lows touched in 2003 and, as a consequence, the estimated average duration of outstanding mortgage-backed securities has shortened appreciably over recent months.