On 11/1/2019, you are looking at Dow Chemical (CUSIP 260543BJ1) corporate bond paying 7.375% fixed (semiannual) coupon and maturing on 11/1/2029. The yield to maturity is 4.58%, implying a yield spread of 188 bps over 10-year Treasury note. Note the day count convention is 30/360.

e. Over a 6-month horizon, how much does the spread have to change for the bond to underperform the 10-year Treasury note? As an approximation, just use the spread duration in (d) and assume that without the change in spread, the bond outperforms the Treasury note by about the magnitude of the credit spread.

{(d. Calculate the modified duration and the spread duration of the bond. Are they the same or different? Why?)}