We investigate the causal impact of corporate governance on equity volatility in a quasi-natural experimental setting by exploiting the staggered passage of governance reforms in the past 25 years. Using a sample of 33,831 firms from 48 countries, we find that equity volatility drops by one-fifth following the passage of reforms that increase board independence. This effect is driven by an adjustment in fixed operating costs as managerial expropriation decreases, rather than by changes in firms’ investments, profitability, asset risk, or financing decisions. We rationalize these findings with a model in which minority shareholders are subject to sticky managerial expropriation.