Answer: Setting the interest rate to zero

The correct answer is C: Setting the interest rate to zero. This approach is recommended because negative short-term interest rates, while theoretically possible, do not align with economic logic as market participants would not lend money at a negative rate when they can hold cash and earn a zero return. To address this issue in the pricing model, the analyst can set all negative interest rates to zero. This method effectively localizes the change to the specific points in the distribution that correspond to negative rates, while keeping the original rate tree intact for all other observations. This is a more targeted and less disruptive adjustment compared to altering risk-neutral probabilities, which would affect the entire range of interest rates and might not be the optimal solution. The explanation also notes that despite the potential for negative rates, the model can still be useful in certain situations, particularly when valuation depends more on the average path of the interest rate, such as in the case of coupon bonds. Therefore, the possibility of negative rates does not necessarily render the model unusable.

Author: LeetQuiz Editorial Team