Sorry, you must have the wrong number allopurinol price goodrx Over the period, rates on primary mortgages and yields on agency mortgage-backed securities (MBS) rose about in line with the 10-year Treasury yield. The option-adjusted spread for production-coupon MBS widened somewhat, possibly reflecting a downward revision in investors' expectations for Federal Reserve MBS purchases, an increase in uncertainty about longer-term interest rates, and convexity-related MBS selling.