On November 26, 2012, the Centers for Medicare & Medicaid Services (CMS) published a proposed rule that would implement ACA provisions related to fair health insurance premiums, guaranteed insurance availability and renewability, statewide insurance risk pools, enrollment in catastrophic plans, and insurance rate reviews. Among other things, the proposed rule would prohibit health insurance companies from denying coverage to individuals because of a pre-existing or chronic condition. The proposed rule also would establish limited circumstances under which insurance companies would be allowed to vary premiums within limits, based on age, tobacco use, family size, and geography. The provisions of the proposed rule generally would be effective January 1, 2014. CMS will accept comments on the proposed rule until December 26, 2012.