We model managers' equilibrium strategies for voluntarily disclosing information about their firm's risk. We consider a multifirm setting in which the variance of each firm's future cash flow is uncertain. A manager can disclose, at a cost, this variance before offering the firm for sale in a competitive stock market with risk-averse investors. In our partial disclosure equilibrium, managers voluntarily disclose if their firm has a low variance of future cash flows, but withhold the information if their firm has highly variable future cash flows. We establish how the manager's discretionary risk disclosure affects the firm's share price, expected stock returns, and beta, within the framework of the Capital Asset Pricing Model. We show that whereas one manager's discretionary disclosure of his firm's risk does not affect other firms' share prices, it does affect the other firms' betas. Also, we demonstrate that a disclosing firm has lower risk premium and beta ex post than a nondisclosing firm. Finally, we show that ex ante, the expected risk premium and expected beta of each firm are higher under a mandatory risk disclosure regime than in the partial disclosure equilibrium that arises under a voluntary disclosure regime.
