44. Ginni Rometty

Title: Chairman and CEO, IBM

Country: US

Age: 58

Last year, IBM CEO Ginni Rometty had to break some tough news: The tech company would be abandoning its years-long promise to hit $20 earnings per share by 2015. But the company's top leader has hatched a new plan: IBM will invest $4 billion to grow $40 billion in revenue in areas such as cloud computing, mobile, and big data by 2018. The plan would nearly double what IBM is making in these markets now, though it also means straying from the hardware focus that's defined IBM for decades.

Rometty's mandate is to keep one of tech's most iconic companies — which employs 380,000 people, on par in size with the population of New Orleans — relevant and profitable for the long haul, even if it means changing some of the most fundamental things about the company. The IBM lifer isn't apologizing for adapting. "Reinvention is not about protecting your past," she said at the Fortune Global Forum earlier this year.