Complex sentence: From 1968-2005, served as chairman and CEO of American International Group (AIG), leading it to become the world's 18th largest public company and its largest insurance and financial services corporation during his tenure.
Split into simpler sentences: From 1968-2005, served as chairman and CEO of American International Group (AIG). Lead AIG to become the world's 18th largest public company and its largest insurance and financial services corporation during his tenure.