The last few years have been good for borrowers. New homebuyers could lock in 30-year mortgages with interest rates as low as 3.4% last spring, provided they had excellent credit scores and a sizeable down payment.

In contrast, savers have been hurting since interest rates on savings accounts, bonds and other safe-haven assets have been at historic lows.

Low rates are all thanks to the Federal Reserve's massive bond-buying program, which has intentionally pushed down interest rates in an attempt to stimulate spending and more economic growth.