To attract more clients, banks compete for your business by offering higher rates of interest. But, once they’ve got your account, the interest rate will soon become much lower. The good news is that with a rate guarantee you can make sure that you get the higher interest for a set time.

Some institutions only offer a guarantee that you will receive the introductory rate for six months, while others will guarantee their higher rate for at least a year. And, if you want to earn the best ISA rates, it’s critical that you know exactly how long the rate guarantee lasts.

While a fixed rate ISA account isn’t subject to interest changes, a variable rate account can go from a high rate to a low rate virtually overnight. Understanding the rate guarantee and knowing exactly how long it lasts can prevent you from losing a lot of money on your savings in interest payments.