Securities and Exchange Commission Chairman Elisse Walter may hire as her top lawyer a former enforcement director from the main U.S. derivatives regulator, Bloomberg News reported yesterday. Geoffrey Aronow, a partner at law firm Bingham McCutchen LLP, has been interviewed by Walter and is the leading candidate to become the agency’s general counsel. Aronow would replace Mark Cahn, who is stepping down in January. As the chief lawyer at the agency, the general counsel plays a central role evaluating rules, advising the chairman and representing the SEC in legal disputes.