Complex sentence: Lewis B. Kaden is a Vice Chairman at Citigroup Inc. He manages the bank's human resources, legal, and mergers-and-acquisitions group, as well as Citigroup's Japanese operations.
Split into simpler sentences: Lewis B. Kaden is a Vice Chairman at Citigroup Inc. He has administrative responsibility for several corporate functions within Citigroup. He also manages the bank's human resources, legal, and mergers-and-acquisitions group, as well as Citigroup's Japanese operations.