Explain why you agree or disagree with the following statement: "The price of an inverse floater will increase when the reference rate decreases."

Question

What will be an ideal response?

Answer 1

As explained below, one would disagree with the statement: "The price of an inverse floater will increase when the reference rate decreases."
The factors that affect the price of an inverse floater are affected by the reference rate only to the extent that it affects the restrictions on the floater's rate. This is quite an important result. Some investors mistakenly believe that because the coupon rate rises, the price of an inverse floater should increase if the reference rate decreases. This is not true. The key in pricing an inverse floater is how changes in interest rates affect the price of the collateral. The reference rate is important only to the extent that it restricts the coupon rate of the floater. More details are given below.

In general, an inverse floater is created from a fixed-rate security. The security from which the inverse floater is created is called the collateral. From the collateral two bonds are created: a floater and an inverse floater. The two bonds are created such that (1) the total coupon interest paid to the two bonds in each period is less than or equal to the collateral's coupon interest in each period, and (2) the total par value of the two bonds is less than or equal to the collateral's total par value.

Suppose the total par value of the floater and inverse floater equals the par value of the collateral. Regardless of the level of the reference rate, the combined coupon rate for the two bonds is equal to the coupon rate of the collateral. However, if the reference rate exceeds a certain percentage, then the formula for the coupon rate for the inverse floater will be negative. To prevent this from happening, a floor is placed on the coupon rate for the inverse floater. Typically, the floor is set at zero. Because of the floor, the coupon rate on the floater must be restricted so that the coupon interest paid to the two bonds does not exceed the collateral's coupon interest. Thus, when a floater and an inverse floater are created from the collateral, a floor is imposed on the inverse and a cap is imposed on the floater.

The price of an inverse floater is found by determining the price of the collateral and the price of the floater. This can be seen as follows: collateral's price = floater's price + inverse's price. Therefore, inverse's price = collateral's price – floater's price.