The effect of mandatory securities regulation on firm value has been a long-standing concern across law, economics, finance, and accounting. The Jumpstart Our Business Startups (JOBS) Act relaxed disclosure and compliance obligations under US securities law for a new category of firms known as “emerging growth companies” (EGCs). EGCs were defined retroactively to include firms that conducted initial public offerings (IPOs) between December 8, 2011, and the enactment of the Act on April 5, 2012. We analyze market reactions for EGCs around key legislative events in March 2012, relative to a control group of otherwise similar firms that conducted IPOs in the months preceding the cutoff date. We find positive and statistically significant abnormal returns of between 3% and 4% for EGCs around the most important of these dates. This suggests that the value to investors of the disclosure and compliance obligations relaxed under the JOBS Act is outweighed by the associated compliance costs.