Privileged Information Exacerbates Market Volatility

We study how asymmetric information affects market volatility in a linear setup where the outcome is determined by forecasts about this same outcome. The unique rational expectations equilibrium will be stable when it is the only rationalizable solution. It has been established in the literature that stability obtains when the sensitivity of the outcome to agents' forecasts is less than 1, provided that this sensitivity is common knowledge. Relaxing this common knowledge assumption, instability obtains when the proportion of agents who a priori know the sensitivity is large, and the uninformed agents believe it is possible that the sensitivity is greater than 1