Movements in interest rates influence a firm’s cash flow and the value of its collateral, all else being equal. Higher interest rates also adversely affect consumer spending and especially residential investment, both by forcing households to devote a greater portion of their income to debt service and by making it more difficult to qualify for a loan because of maximum payment-to-income rules.
Evidence for these effects is provided by Gertler and Karadi (2015), who show that relatively small changes in short-term interest rates are correlated with large movements in credit costs. Such correlations and interactions may explain why some types of spending appear to be more correlated with movements innominal interest rates than with real interest rates; see Fair (2004, ch.