What is the definition of a Fixed Income (FI)?

A fixed income asset is any asset that provides a constant stream of periodic income, the most common form being a bond. Due to the fact that the income is constant, it is easier to value the future cash flows of a bond than it is to do so on a stock or commodity, therefore making fixed-income assets fantastic for trading, however, inflation can devalue the future returns.

Typically, the yield paid on a fixed asset is inverse to the price (i.e. yield goes up as price goes down). The reasoning behind this is that as an asset becomes more attractive, the issuer (borrower) has to pay less interest to the buyer in order to get the buyer to lend him money.