Complex sentence: Leland served as President of the American Finance Association in 1997, and has served on numerous scientific advisory boards, including those of Goldman Sachs, Wells Capital Management, the Chicago Mercantile Exchange, and the Swiss National Science Foundation.
Split into simpler sentences: Leland served as President of the American Finance Association in 1997. He has served on numerous scientific advisory boards, including those of Goldman Sachs, Wells Capital Management, and the Chicago Mercantile Exchange, and the Swiss National Science Foundation.