Garrett Walls left JPMorgan Investment Management after about three months as head of U.S. institutional business. The firm is working on a succession plan, and despite the departure, "our institutional business is in very good shape," said Jacqueline Meere, a JPMorgan spokeswoman. Mr. Walls, who had been at JPMorgan for 14 years, left to pursue "other opportunities," she added. He succeeded Eve Guernsey, who was promoted to president of JPMorgan Investment Management. Before his promotion, Mr. Walls was head of West Coast institutional sales. He could not be reached for comment, but a source familiar with the situation said Mr. Walls joined Trust Company of the West as director of institutional sales. TCW spokesman Michael Utley declined to comment.