Terry Myerson, executive vice president of operating systems
A major heavyweight in the lineup for next CEO, Myerson has been with Microsoft since 1997, when the Redmond giant acquired Inters the web software company he had founded five years earlier at the age of 21.
Myerson became head of mobile engineering in 2008 and was promoted to lead the Windows Phone division in 2011.
He was another of the company's senior employees to receive a promotion in the July reshuffle, which led to The Verge naming him "the most important man at Microsoft".
Very few criticisms can be levelled at this rapid rising star, although some have pointed to Windows Phone not being as successful as it was expected to be, lagging significantly behind Apple's iPhone and Google's Android offerings in terms of market share.
Satya Nadella, executive vice president of cloud and enterprise
Nadella is another long-term employee of Microsoft, having joined the company from Sun Microsystems in 1992.
He has held several senior positions at the organisation, including senior vice president of R&D at the online services division, vice president of the Microsoft business division and president of the Server and tools business.
Nevertheless, it has been argued that Nadella does not have the technology vision to truly enable Microsoft to take on its nemeses Google and Apple in the consumer technology market.
Jeff Raikes, CEO of Bill & Melinda Gates Foundation
Jeff Raikes is the longest serving employee to make the list, having been recruited by Ballmer to the position of product manager in 1981.
He served in many different roles before rising to become president of the Microsoft business division. In 2008 he left Microsoft, having been hand picked by Bill Gates to run the philanthropic organisation he set up with his wife, The Bill & Melinda Gates Foundation.
His long service with the company puts him on this list, however some are concerned that his five years outside the business may mean he is less in touch with current trends than other contenders.
Eric Rudder, executive vice president of advanced strategy and research
Rudder has been with Microsoft for around 20 years and was once tipped to take over as CEO from Bill Gates, so it is perhaps not surprising to find him on this list.
Previous to his current position, he was senior vice president of Server and Tools and, prior to that, worked directly with Bill Gates as vice president of technical strategy.
However, he has never been a business unit leader and was, of course, passed over once before in favour of Ballmer.
