Evergreen Health Cooperative must pay $24.2 million to its biggest competitor because of an Affordable Care Act program that aims to level the playing field for insurers taking on riskier customers from state health insurance exchanges.

Evergreen, an innovative insurer established under the new law by former Baltimore Health Commissioner Peter Beilenson, is not alone in having to pay for its healthier clients. Kaiser Permanente of the Mid-Atlantic States owes $14.7 million and Aetna will shell out $11.8 million.