An Affordable Care Act-initiated rule striking at the heart of some health insurers’ profit margins has landed at the White House for review.

The provision involves medical ratio loss requirements — insurer-speak for the amount of money healthcare plans must devote to medical expenses versus what they can take for overhead costs and profit.

Drafted by the Department of Health and Human Services (HHS), the proposed rule covering Medicare Advantage plans and prescription drug benefit programs was submitted Thursday to the White House’s Office of Information and Regulatory Affairs (OIRA).

The proposed regulation is considered economically significant in that it would carry an economic impact of more than $100 million. The measure’s actual cost will depend on its details.