Over the past twenty years, the monetary aggregates used by the Federal Reserve as indicators of economic activity and inflation have changed several times. Each of the changes in the measures of money was sparked by a breakdown in the fit of empirical money demand functions. The Federal...

This paper explores the instability in estimated money demand functions. Using a new data series on credit card usage, we evaluate the role of financial innovations in stabilizing the M1 demand function over three troubling episodes. We find that our measure of financial innovations improves the...