The ACA introduced the medical loss ratio (MLR) requirement to the individual, small group, and large group markets with the stated goal of improving the value and affordability of health insurance benefits by capping insurers’ profit margins and administrative costs. The requirement requires insurers to spend a large percentage of premium revenue on medical services—80 percent for individual and small group plans, and 85 percent for large group plans—thereby limiting administrative costs and profits to the remaining 15–20 percent. After more than a decade, there is little evidence that the MLR requirement has promoted premium affordability or constrained insurer profits as intended; instead, the MLR drives higher premiums and higher medical care spending and presents other unintended consequences that warrant attention. The Unintended Consequences Of The MLR Requirement: 1. Driving Premium Inflation 2. Incentivizing Insurer Consolidation 3. Deterring Innovative And Affordable Plans The MLR requirement is well-intentioned, but its cost-plus design is flawed. By capping insurer overhead and profit margins without addressing the structural drivers of unaffordable health care, the requirement unintentionally incentivizes insurers to prioritize horizontal and vertical integration over cost containment and innovation. These dynamics compromise plan quality, reduce enrollees’ choices of affordable plans, and increase taxpayer burdens. Appreciate my coauthors: @RandyPate15 @SunjayLetchuman, Elizabeth Plummer, Xiaoxi Zhao, Joshua Brooker, & Lynn Lewis. @JHUCarey @JohnsHopkinsSPH @BSPH_HPM @Health_Affairs Forefront link: