AbstractWe investigate how nonfinancial disclosure laws exacerbate agency issues in firms. Our analysis focuses on the staggered adoption of state‐level notification laws that require firms to disclose data breaches. Our findings reveal that the introduction of these laws increases the risk of stock price crashes. Managers appear motivated to accumulate unfavorable news in an effort to prevent market overreactions associated with the mandatory disclosure of data breaches. Cross‐sectional analyses also reveal that the impact is stronger when managers have a greater incentive, or greater ability, to hoard information. Our results highlight that nonfinancial disclosures can have unintended consequences for firm information asymmetries and potentially adverse market impacts in cases where the regulation is unable to consider all stakeholders.