Abstract: We analyze a model in which firms are able to acquire information about product risks and may or may not be required to disclose this information. We initially study the effect of disclosure rules assuming that firms are not liable for the harm caused by their products. Mandatory disclosure is obviously superior to voluntary disclosure given the information about product risks that firms possess, since such information has value to consumers. But firms acquire more information about product risks under voluntary disclosure because they can keep silent if the information is unfavorable. This effect could lead to higher social welfare under voluntary disclosure. The same result holds if firms are liable for harm under the negligence standard of liability. Under strict liability, however, mandatory and voluntary disclosure rules are equivalent because information concerning product risks is irrelevant to consumers.