Central Bank's interventions and the Fisher hypothesis: a threshold cointegration investigation

The long-run relationship between nominal interest rates and inflation is examined, allowing for structural breaks and asymmetric mean reversion. From a Threshold AutoRegressive (TAR) test applied to the residuals of the cointegration relationship (while allowing for both a break in the mean of the long-run equation and a smooth regime-transition), there is strong evidence for non-linear mean reversion properties for the real interest rates of the US Treasury Bill market. This suggests asymmetric changes to inflation shocks in the Central Bank's reaction function. The existence of different regimes is consistent with some interpretations of the monetary policies run by the Fed, such as credibility and opportunism.