Home Depot Inc. /zigman2/quotes/208081807/composite HD -1.67% said late Thursday its board has authorized a new $15 billion share buyback program, replacing a previous authorization. In a separate announcement, the specialty retailer said that the board has elected Chief Executive and President Ted Decker as chair, effective Oct. 1. Decker will succeed Craig Menear, who will retire as chair on Sept. 30, the company said. Home Depot named Decker as CEO in January, and at the time also announced that then-CEO Menear would continue to serve as chairman of the board. Home Depot shares rose 1.2% in the extended session Thursday after ending the regular trading day down 0.2%.