You manage a portfolio of GM bonds and run a regression of your bond’s price changes on the changes in the S&P 500 index futures and changes in the 10-year Treasury note futures. The regression result is as follows: 

Where the regression above is in changes in index values for all the right-hand side variables. What positions in the two index futures will you take? What proportion of the risk remains unhedged? What implicit assumption might you be making in this case?