The Centers for Medicare and Medicaid Services (CMS) issued proposed rules on July 15 on reinsurance, risk corridors, and risk adjustments to mitigate potential financial risks to health insurance plans under health care reform. The proposed rules are based on section 1341 of the Affordable Care Act (ACA) which requires each state to establish a reinsurance program to help stabilize premiums in the individual health insurance market for the first three years of exchange operations (2014-2016); section 1342 of the ACA which requires CMS to implement a risk corridor program in the individual health insurance market and the small group health insurance market over the same three year period; and section 1343 of the ACA which permits states to create risk adjustment programs in the individual and small group markets over a longer period if desired.  These ACA provisions recognize that it will be unusually difficult for each health insurance plan to project its annual revenues and expenses with precision as millions of previously uninsured persons with unknown health status begin to enroll. The proposed rules seek to spread these risks equitably. Comments on the proposed rule are due September 28.