This study investigates if the reaction function of the Federal Reserve switches between two distinct policy rules. Using a time-varying transition probability framework, we also determine if forward-looking macroeconomic or financial covariates signal an impending monetary regime switch. We find that US monetary policy is best described by a Markov-switching model with two regime processes, one of which controls for heteroskedasticity in the shocks to the policy rule. We find that the Fed switches between an aggressive regime with a relatively high weight on inflation and a dovish regime that is less responsive to inflationary pressures. We find that an increase in private forecasters’ expectations of an impending recession signals a switch from the more aggressive policy regime to the less aggressive regime. A recovery in equity returns signals a return back to the more aggressive regime.