The U.S. Supreme Court ruled in favor of health insurers seeking $12 billion from the federal government under a program set up by the Obamacare law aimed at encouraging them to offer medical coverage to previously uninsured Americans.

Centene Corp. will buy smaller rival WellCare Health Plans Inc. for $15.27 billion in stock and cash, in a move to bulk up the U.S. health insurer’s government-backed Medicare and Medicaid businesses while reducing exposure to Obamacare healthcare exchanges.