A trader laughs while working on the floor of the New York Stock Exchange in New York, Thursday, Jan. 31, 2013. The Dow edged higher Thursday, keeping the index on track for its best st

 

              A trader laughs while working on the floor of the New York Stock Exchange in New York, Thursday, Jan. 31, 2013. The Dow edged higher Thursday, keeping the index on track for its best st
A trader laughs while working on the floor of the New York Stock Exchange in New York, Thursday, Jan. 31, 2013. The Dow edged higher Thursday, keeping the index on track for its best start to the year in more than two decades. (AP Photo/Seth Wenig)*