Monetary and Macroprudential Policies under Fixed and Variable Interest Rates

In this paper, I analyze the ability of monetary policy to stabilize both the macroeconomy and nancial markets under two different scenarios: fixed and variable-rate mortgages. I develop and solve a New Keynesian dynamic stochastic general equilibrium model that features a housing market and a group of constrained individuals who need housing collateral to obtain loans. A given share of constrained households borrows at a variable rate, while the rest borrows at a fixed rate. I consider two alternative ways of introducing a macroprudential approach to enhance nancial stability: one in which monetary policy, using the interest rate as an instrument, responds to credit growth; and a second one in which the macroprudential instrument is instead the loan-to-value ratio (LTV). Results show that when rates are variable, a countercyclical LTV rule performs better to stabilize financial markets than monetary policy. However, when they are fixed, even though monetary policy is less effective to stabilize the macroeconomy, it does a good job to promote financial stability.