  A simple spin model is studied, motivated by the dynamics of traders in a
market where expectation bubbles and crashes occur. The dynamics is governed by
interactions which are frustrated across different scales: While ferromagnetic
couplings connect each spin to its local neighborhood, an additional coupling
relates each spin to the global magnetization. This new coupling is allowed to
be anti-ferromagnetic. The resulting frustration causes a metastable dynamics
with intermittency and phases of chaotic dynamics. The model reproduces main
observations of real economic markets as power-law distributed returns and
clustered volatility.
