CEO of the Minnetonka-based health care insurer and services company since 2017, David Wichmann is leading UnitedHealth through especially tempestuous times in his industry. He certainly knows it well. He’s been with UHC since 1998, holding executive positions including CFO and president. UnitedHealth remains the largest health care company in the world by revenue—$226.2 billion in 2018—and is ranked No. 6 on the 2019 Fortune 500 list. Under Wichmann, UnitedHealth has launched an ACA-inspired “accountable care platform” intended to lower costs by focusing on health outcomes.