
The latent factors behind commodity price indices
A 35-year empirical study suggests that about one third of the monthly changes in a broad commodity price index can be attributed to a single global factor that is related to the business cycle. In fact, for a non-fuel commodity basket almost 70% of price changes can be explained by this factor. By contrast, oil and energy price indices have been driven mainly by a fuels-specific factor that is conventionally associated with supply shocks. Short-term price changes of individual commodities depend more on contract-specific events, but also display a significant influence of global and sectoral factors. The latent global factor seems to help forecasting commodity index prices at shorter horizons.