The Affordable Care Act (ACA) was signed into law a decade ago. Partisanship has limited the number of statutory changes, leaving the law mostly unchanged across the past 10 years. However, the ACA delegated vast powers to the executive branch, which opened the door for significant regulatory policy-making activities (also called “rulemaking”). We collected data on all regulatory actions related to the Affordable Care Act that have been taken since its passage to provide the first exploratory analyses of both the public law itself and the ensuing rulemaking activities. We also provide illustrative examples of two controversial issues: short-term limited-duration insurance plans and contraceptive coverage for women. Despite relative statutory stasis, regulatory actions have continued to shape the implementation of the Affordable Care Act. Both the Obama and Trump administrations have taken advantage of a vast delegation of policy-making power. Importantly, regulatory policy making holds the potential to yield significant changes depending on the policy goals of the presidential administration. Scholars, policy makers, and the public are well-advised to pay attention to ACA-related rulemaking activities. Moreover, “quasi-rulemaking” (i.e., the use of agency guidance as a policy tool) remains largely unexplored but could indicate an even greater regulatory enterprise than illustrated here.