DuPont’s share price was in a 10-year slump when Kullman took over in 2009. Since then, she’s moved the 212-year-old company into higher-margin areas like nutrition, advanced materials, and bioscience. She sold the auto paints unit in 2013 and will shed performance chemicals like Teflon and Freon next year. Investors seem to like the moves: DuPont’s market cap has more than doubled during her tenure.