Highmark Health has announced that its president and chief executive, David Holmberg, will become chairman of the board of directors of Highmark, Inc., one of its subsidiaries. Holmberg was named Highmark Health's president and chief executive in May 2014. Most recently, he was president of diversified businesses for Highmark, Inc. In addition, the group said that J. Robert Baum is stepping down as chairman of the board and will be succeeded by Joseph C. Guyaux, senior vice chairman of The PNC Financial Services Group and president and chief executive of PNC Mortgage. Guyaux has worked at PNC for 42 years. Both changes became effective on Feb. 25. Baum will continue to serve as a member of the board of directors of HVHC, Highmark Health's vision affiliate, which includes Davis Vision and Visionworks. He will also join the board of directors of HM Insurance Group and the board of directors of United Concordia, Highmark Health's dental affiliate.