Elaine La Roche, who became one of the most powerful women on Wall Street when women there were scarce — notably helping to orchestrate the first partnership between an American investment bank, Morgan Stanley, and the government of China — died on Aug. 25 2019 at her farm in Sharon, Conn. She was 70. Her daughter Eve La Roche said the cause was pancreatic cancer. In her 22 years with Morgan Stanley, she was an integral participant in the creation of the China International Capital Corporation, a landmark joint venture in 1995 between Morgan Stanley and the government-run China Construction Bank. Ms. La Roche soon moved to Beijing to be chief executive of the corporation, a post she held from 1997 to 2001. She became a respected China expert and was lauded for earning the trust of her Chinese counterparts. She later served as vice chairwoman of JP Morgan China Securities in Beijing from 2008 to 2010 and for a time was chief executive of the China International Capital office in the United States. By 1996 she had risen to managing director, making her the highest-ranking woman at one of the most powerful firms on Wall Street. Marie-Elaine Andree La Roche was born in Manhattan on Aug. 17, 1949, to Andre and Madeleine (Hanin) La Roche, and grew up in northern New Jersey. Her father, an immigrant from Haiti, was a civil engineer for the Port Authority of New York and New Jersey; her mother, from France, was a schoolteacher. She graduated from the Georgetown University School of Foreign Service in 1971 and went on to earn an M.B.A. from American University in Washington. Before arriving on Wall Street, she was an assistant first to Donald H. Rumsfeld, when he was a Republican congressman from Illinois, and then to George P. Shultz, when he was secretary of the Treasury under President Richard M. Nixon. Ms. La Roche married Peter Donovan, a geologist, in 1988. The couple adopted two children from Honduras, Felicia and Nicholas. The marriage ended in divorce. Ms. La Roche was 45 when she had her daughter Eve with her partner at the time, the playwright Lonnie Carter. In addition to Eve La Roche, she is survived by her other children and her brother, Andre La Roche Jr.