BGI, a leading provider of index-tracking funds, is run by chief executive Pattie Dunn, 49, one of America's best-known female bosses. The daughter of a Las Vegas showgirl and a vaudeville performer, she began her career at BGI as a temporary secretary. Dunn, who is married with four stepchildren, at first refused to take a permanent post. She says: 'I had no intention of working for a bank. I thought I'd rather take chloroform and die.'