Blue Shield of California properly calculated how much money it owed plan members under an Obamacare program meant to guarantee insurers use the bulk of their premiums to pay for medical care, an appeals court said.

The insurer didn’t err when it included $38 million it paid to members to settle unreimbursed claims when it calculated its medical loss ratio for 2014, the U.S. Court of Appeals for the Ninth Circuit said March 18. This is the first federal appeals...