A hedge fund's capital structure is fragile because uninformed fund investors are highly loss sensitive and easily withdraw capital in response to bad news. Hedge fund managers, sharing common investors and interacting with each other through market price, sensitively react to other funds'...

Building on the notion that bubbles are transient self-fulfilling prophecies created by positive feedback mechanisms, we construct the simplest continuous price process whose expected returns and volatility are functions of momentum only. The momentum itself is measured by a simple continuous...