IBM recently announced that Palmisano will step down at the end of the year, handing over the reins to longtime senior executive Ginni Rometty. Palmisano leaves on a high note: This
fall, IBM's market cap briefly exceeded that of Microsoft's, making IBM the world's second-most-valuable tech company after Apple. The company's shares have tripled since he took over
from Louis Gerstner in 2001, and Warren Buffett's Berkshire Hathaway this year accumulated a 5.5% stake in IBM.