He owns nearly 1.6 million Morgan Stanley shares worth some $28 million, making him the second-largest shareholder among company executives after CEO James Gorman, according to Morgan Stanley's latest proxy statement. Taubman has been a longtime supporter of Obama, dating back to the 2008 Democratic presidential primary, when he was responsible for bringing the candidate to meet with several of the firm's top executives. The person close to Taubman says he would be a suitable candidate for several government positions, including Deputy Treasury Secretary or Director of the National Economic Council. Taubman's departure from Morgan Stanley allows Colm Kelleher, the other co-head of institutional securities, to take sole responsibility for the business. The rivalry between the two men was well-known, and was the subject of stories in both The New York Times and Bloomberg News in 2011.