Fortune's Most Powerful Women in Business

President and CEO of IBM, Ginni Rometty, tops Fortune magazine's 2012 list of 50 most powerful women in business. Rometty has been at IBM for 31 years and is the company's first female CEO. The 55-year-old helped develop IBM's five-year growth plan that she's been in charge of since she started her post on Jan. 1. Last year, Rometty ranked seven on Fortune's list. (PatrickMcMullan/AP Images)