Because real estate investment trusts essentially represent a fixed-income portfolio, their market values will as interest rates increase.

The correct words for the blank space are:  mortgage; decrease.

Explanation:

A mortgage is a loan used to purchase a home where the property serves as the borrower's collateral. If included within a portfolio, they represent a fixed-income portfolio because their market value will decrease if interest rates are raised. This is because the higher is an interest rate, the lesser people will be able to afford to pay for them thus home prices will have to go down so that they can be purchased.

answer; buying the bill at a discount from the face value to be received at maturity;