President Bush reportedly is expected to name Wall Street executive William Donaldson as the new chairman of the Securities and Exchange Commission. Media reports said an announcement was planned for later Tuesday. Donaldson would replace SEC Chairman Harvey Pitt, who resigned in November amid a slew of corporate scandals. Donaldson founded the investment banking firm Donaldson Lufkin & Jenrette. He also served as chairman and chief executive of the New York Stock Exchange from 1990 to 1995. He was a founder of Yale University's Graduate School of Management. Bush's expected selection of Donaldson comes a day after he nominated railroad executive John Snow for the post of Treasury secretary, replacing Paul O'Neill.