Do more talented traders prefer to bet on and against rare events or common events? Bets on rare events include out of the money options. Bets against rare events include the carry trade and investment grade bonds. In a model where traders specialize, equilibrium pricing reflects trading ability: A market with more skilled traders has a larger bid ask spread. We show that lower skill traders bet on and against rare events, while higher skill traders bet on and against frequent events, leading to higher bid-ask spreads in common event assets, and reducing financial markets’ ability to predict rare events.

Will arbitrage capital flow into markets experiencing shocks, mitigating adverse effects on price efficiency? Not necessarily. In a dynamic model with privately informed capital-constrained arbitrageurs, price efficiency plays a dual role, determining both the profitability of new arbitrage and the ability to close existing positions profitably. An adverse shock to efficiency lengthens arbitrage duration, effectively reducing the amount of arbitrage capital available for new positions. If this falls below a critical mass, arbitrage capital flows out, amplifying the impact on price efficiency. This creates endogenous regimes: temporary shocks can trigger “hysteresis,” a persistent shift in price efficiency.