Provided by Dow Jones By Juliet Chung Morgan Stanley's global head of prime brokerage, Edward Keller, is stepping down from his role to deal with a personal health issue, the bank said in an internal memo Monday. The bank named Penny Novick and Kim Shaw as global co-heads of prime brokerage to succeed Mr. Keller. The pair are the first women Morgan Stanley has named to run prime brokerage globally. Mr. Keller is a nearly 30-year veteran of Morgan Stanley. The memo said Mr. Keller had told the bank about his wish to step down and that he would return to a senior role advising clients, reporting to the global co-heads of institutional equities. Prime brokers cater to trading clients such as hedge funds, executing their trades, lending them money and helping introduce them to investors.