The youngest-ever female CEO of a Fortune 500 company is fighting Trump’s cuts to keep Medicaid strong

Sarah London operates on the front lines of the toughest terrain in U.S. health care. She’s the CEO of Centene, an insurance giant providing government-sponsored plans at a time when funding is tight, costs are rising, and policy shifts create intense uncertainty.

While the St. Louis–based managed care insurer saw revenue grow almost 20% last year, to $194.8 billion, it posted a net loss of $6.7 billion. That was largely driven by a write-down that reflected the new reality for health...