Final answer:
The unexpected gain or loss is the difference between the expected and actual rates of return, influenced by the risk associated with the investment.
Step-by-step explanation:
The difference between the expected rate of return and the actual rate of return is referred to as the unexpected gain or loss. The expected rate of return estimates future earnings from an investment such as interest payments, capital gains, or increased profitability, and is typically projected over several years.
On the other hand, the actual rate of return is the total yield on an investment, combining capital gains and interest received over a specific period. Risk evaluates the degree of uncertainty involved in an investment's returns, with default risk and interest rate risk being prominent examples. High-risk investments may yield returns that significantly deviate from expectations, while low-risk ones tend to produce results closer to their anticipated returns.