Final answer:
Dave's major investment risk is Interest Rate Risk.
Step-by-step explanation:
In this scenario, Dave's major investment risk is Interest Rate Risk. Interest rate risk refers to the possibility that changes in interest rates may negatively impact the value of an investment. Given that Dave has investments in a 5-year GiC, a high interest savings account, and a money market segregated fund, all of which are sensitive to interest rate fluctuations, he is exposed to this risk.