I examine how money and trend inflation shaped US macroeconomic dynamics during the Great Inflation. I develop a business cycle model with positive trend inflation where money is allowed (but not required) to play a role in determining the equilibrium values of inflation and output through non-separable utility, adjustment costs for holding real balances, and the monetary policy reaction function. The Taylor principle changes in this environment. Targeting money guarantees price determinacy even with trend inflation, but these results are sensitive to the inclusion of non-separability and portfolio adjustment costs. The framework is combined with Greenbook data that detect the role of money in the policy reaction function. The response to money was likely not sufficiently strong to complement the reaction to inflation and counteract the high trend inflation observed during the pre-Volcker period, which most likely led to price indeterminacy.

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.