UnitedHealth Group CEO Andrew Witty is stepping down as the chief executive and will be succeeded by Stephen J. Hemsley, the healthcare giant announced on Tuesday. 

Witty has stepped down from the post for “personal reasons” and will now serve as the senior adviser to Hemsley. 

Hemsley, who was the company’s CEO from 2006 to 2017, will also maintain his role as the chairman of the insurance company’s board of directors. 

“We are grateful for Andrew’s stewardship of UnitedHealth Group, especially during some of the most challenging times any company has ever faced,” Hemsley said Tuesday in a statement. “The Board and I have greatly valued his leadership and compassion as chief executive and as a director and wish him and his family the best.

“UnitedHealth Group has tremendous opportunities to grow as we continue to help improve health care and to perform to our potential — and, in so doing, return to our long-term growth objective of 13 to 16 percent,” he added.

The company was thrust into the spotlight late last year after then-CEO Brian Thompson was gunned down in Manhattan on his way to an investors’ conference. The man accused of killing Thompson is Luigi Mangione, who was arrested at a McDonald’s in Altoona, Pa., after a five-day search. 

A New York federal grand jury indicted Mangione last month on four counts, including a firearms charge, stalking and murder through the use of a firearm. If convicted of those counts, he would be eligible for the death penalty, a punishment that Attorney General Pam Bondi has pushed for. He has pleaded not guilty,

Mangione also faces state charges in New York and Pennsylvania related to the December shooting in New York City. He has pleaded not guilty in both cases as well.