Wiemann: The Pros And Cons Of Low-Rate Borrowing As A Business Owner CERTIFIED FINANCIAL PLANNER™ Professional For those with high creditworthiness, low interest rates may present an opportunity to consolidate existing debt or pursue new areas of growth. The federal funds rate has been called “the most important interest rate in the world.” This interest rate is the rate that banks pay for overnight borrowing – and it sets the stage for the prime rate and every other interest rate across the spectrum. From mortgages to credit cards, loans to car financing, the fed funds rate can have a powerful effect throughout the rest of the economy.