Americans who purchase health insurance on the Affordable Care Act’s exchanges should buckle up. Within the month, state regulators will begin approving premium hikes for plans sold in every state. The Centers for Medicare and Medicaid Services (CMS) has already released the premium increases that health insurers have requested for their 2016 plans. By law, insurers must receive regulatory approval for any increase more than 10%—and more than 10% is what many of them want.

The numbers are staggering. According to the rate...