UPDATE 1-Vanguard CIO Buckley to take over as CEO from McNabb on Jan. 1
July 13, 2017 at 18:11 PM EDT
BOSTON, July 13 (Reuters) - Vanguard Group, the world's largest mutual fund manager, said on Thursday Chief Executive Bill McNabb will step down at year end and be replaced by Chief Investment Officer Tim Buckley, betting on the internal successor to oversee rapid growth.