Prices of mortgage backed securities held to a tight range yesterday, closing the day in essentially the same place they opened. The lack of volatility in MBS prices allowed lenders to keep mortgage rates near five month lows. Yesterday's main event, besides weakness in the dollar and record high gold prices, was the Treasury Department auction of $39billion 3 year notes. Auction demand could be described as below average, but not weak enough to warrant a rise in rates. Strong demand for our nation’s debt is one of the main factors helping to keep mortgage rates near historic lows....