Intel
Apple
CEO of Apple (AAPL) since 2011 The operations whiz, 51, may eventually be succeeded by a younger, Jobsian visionary ... Scott Forstall
Senior VP, iOS ... like the 43-year-old mobile-software chief. He runs Apple's cash-cow iPhone business.
Microsoft
CEO of Microsoft (MSFT) since 2000 Ballmer, 56, has been criticized for Microsoft's lackluster performance in handsets and search. Steven Sinofsky
President, Windows and Windows Live A smooth launch of Windows 8 could propel the 46-year-old.
Cisco Systems
CEO of Cisco (CSCO) since 1995 The 63-year-old chief recently said he may retire within the next four years. Robert Lloyd
EVP, Worldwide Operations Lloyd, 56, has hung in for two decades and is frequently named as a possible next in line.
Oracle
CEO of Oracle (ORCL) since 1977 After 3 1/2 decades, the feisty 68-yearold shows no signs of slowing down. Safra Catz
Co-President and CFO Does the veteran, 50, have the upper hand for succession over co-president Mark Hurd?