The sharp peak-flat trough pattern and critical speculation

We find empirically a characteristic sharp peak-flat trough pattern in a large set of commodity prices. We argue that the sharp peak structure reflects an endogenous inter-market organization, and that peaks may be seen as local “singularities” resulting from imitation and herding. These findings impose a novel stringent constraint on the construction of models. PACS numbers : 01.75+m Science and society 05.40.+j Fluctuation phenomena, random processes, and Brownian motion 05.70.Jk Critical point phenomena 89.90.+n Other areas of general interest to physicists