UnitedHealth Group will promote one of its top insurance executives to replace Brian Thompson, the slain CEO of its UnitedHealthcare arm.

UnitedHealthcare announced a new CEO on Thursday, filling in the spot after Brian Thompson was shot and killed in December in what authorities have called a targeted attack.

The new CEO of Minnesota-based UnitedHealthcare takes the helm of a company whose former leader was killed in December.

UnitedHealth Group on Thursday named Tim Noel, the head of its Medicare business, to the top job at its health insurance business, a month after the unit's former CEO Brian Thompson was killed. Noel ...