Recent crises have seen large spikes in asset price risk. We propose an explanation for such panics based on self-fulfilling shifts in beliefs about risk. A negative link between the current level and the future risk of an asset price leads to a circular relationship between the stochastic process of asset price risk and the price itself. Self-fulfilling shifts in perceived risk can be coordinated around a pure sunspot or around a macro fundamental. In a risk panic, a macro fundamental can be a focal point that affects both the magnitude of the panic and subsequent shifts in perceived risk.

There has been a long debate about whether speculators are stabilizing or not. We consider a model where speculators have a stabilizing role in normal times, but may also provoke large risk panics. The very feature that makes arbitrageurs liquidity providers in normal times, namely their tolerance of risk, enables a large increase in asset price risk during a financial panic. We show that a policy that discourages balance sheet risk reduces the magnitude of financial panics, as well as asset price risk in both normal and panic states.