Expectations theory attempts to predict what short-term interest rates will be in the future based on current long-term interest rates. The theory suggests that an investor earns the same amount of interest by investing in two consecutive one-year bond investments versus investing in one two-year bond today. The theory is also known as the "unbiased expectations theory."

Understanding Expectations Theory

The expectations theory aims to help investors make decisions based on a forecast of future interest rates. The theory uses long-term rates, typically from government bonds, to forecast the rate for short-term bonds. In theory, long-term rates can be used to indicate where rates of short-term bonds will trade in the future.

Example of Calculating Expectations Theory

In this example, the investor is earning an equivalent return to the Let's say that the present bond market provides investors with a two-year bond that pays an interest rate of 20% while a one-year bond pays an interest rate of 18%. The expectations theory can be used to forecast the interest rate of a future one-year bond.

The first step of the calculation is to add one to the two-year bond‘s interest rate. The result is 1.2. The next step is to square the result or (1.2 * 1.2 = 1.44).

Divide the result by the current one-year interest rate and add one or ((1.44 / 1.18) +1 = 1.22).

To calculate the forecast one-year bond interest rate for the following year, subtract one from the result or (1.22 -1 = 0.22 or 22%).

the present interest rate of a two-year bond. If the investor chooses to invest in a one-year bond at 18% the bond yield for the following year‘s bond would need to increase to 22% for this investment to be advantageous.