This paper shows that money is a relevant macroeconomic indicator for the description of US monetary policy with simple rules. Empirical analysis based on novel real-time data reveals the economically and statistically significant effect of money on the federal funds rate during the Volcker–Greenspan era, highlighting an interest rate rule that better explains historical policy. The findings suggest that the bias against including money in mainstream macroeconomic models may be due to relying on an incorrect measure of money. A gradual deviation from this rule explains loose monetary policy prior to the Great Recession. Including money aggregates in rule-based policy presents a suitable framework to evaluate and guide Federal Reserve policy.