Complex sentence: Following his electoral defeat, Lumley returned to the private sector and became an influential corporate figure serving as vice-chairman of BMO Nesbitt Burns since 1991, lead director of Magna International and a board member of Bell Canada Enterprises, Canadian National Railway and Air Canada.
Split into simpler sentences: Following his electoral defeat, Lumley returned to the private sector and became an influential corporate figure. He has served as vice-chairman of BMO Nesbitt Burns since 1991, lead director of Magna International, and a board member of Bell Canada Enterprises, Canadian National Railway and Air Canada.