Commodity Price Changes are Concentrated at the End of the Cycle

This paper introduces a new approach to the analysis of the cyclical behaviour of world commodity prices. Within booms and slumps, the behaviour of commodity prices seems to be quite similar, surprisingly even amongst different types of commodities (soft and hard), which are influenced by different shocks. The key result is that during commodity price booms, the faster growth occurs towards the end of the boom. Likewise, most of the collapse of prices occurs towards the end of slumps. This paper first establishes this behaviour as a new empirical regularity of commodity prices. Secondly, this paper introduces a novel way to conceptualise shocks to commodity prices as a cyclical occurrence, and on the basis of this newly established empirical regularity, the size of these cyclical shocks act as leading indicators of impending turnings points.