Measuring Money Growth When Financial Markets are Changing

This article considers constructing monetary aggregates in the presence of financial market innovations and changes in the relationship between individual assets and output. We propose two procedures for constructing a monetary aggregate with the objective of providing a reliable monetary leading indicator of nominal GDP. In the first, subaggregates discretely switch in and out; in the second, the aggregate's growth is a time-varying weighted average of the growth of the subaggregates, where the weights follow a multivariate random walk. These procedures are used to examine augmenting M2 with stock and/or bond mutual funds. The alternative aggregates are broadly similar to M2, but during 1992–1993 they outperform M2.