Microsoft has a stable of senior executives who could be contenders to succeed CEO Steve Ballmer ? he announced on Friday that he would retire within a year ? even though outsiders have sparked the most discussion so far. Here’s a list of potential candidates (all except Raikes and Thompson are executive vice presidents)

Satya Nadella

PRO: A 21-year Microsoft veteran, he knows the inner workings of the company. Recently promoted to run the newly created ?cloud and enterprise? unit, he controls the infrastructure behind the ?services? side of Microsoft’s new vision

CON: Although he was once a vice president in the Office unit, he might struggle to impose authority over the all-powerful Windows and Office factions, which are famously antagonistic to one another

Tony Bates

PRO: Came to Microsoft two years ago as CEO of the acquired company Skype. He so impressed his new boss that Ballmer put him in charge of corporate strategy and relations with developers and PC makers

CON: May not have been at Microsoft long enough to know how to wrench it into a new shape, and his narrow specialty in the telecommunications and router field may not be broad enough to run such a large software-based company

Terry Myerson

PRO: A young entrepreneur whose web software company was bought by Microsoft in the late 1990s, he might bring a start-up mentality to the top job.

Recently selected by Ballmer to run the full range of operating systems

CON: His last assignment was running the Windows phone unit, which won praise for its clean, stylish software but has not come close to making Microsoft a big player in the smartphone market

Qi Lu

PRO: The former Yahoo executive is a heavyweight in the online search and advertising area, with 20 US patents. He now runs the ?applications and services? group. It is a crucial part of Ballmer’s reorganisation plan.

CON: Under his stewardship, the Bing search engine has cost Microsoft billions of dollars without threatening dominance

Julie Larson-Green

PRO: A 20-year veteran of Microsoft and acolyte of recently departed Windows chief Steven Sinofsky, she has intimate knowledge of both the Office and Windows units, having led the redesign of both products

CON: Is in charge of the ?devices and studios? unit, leading Microsoft’s foray into making its own computers and other hardware. The Surface tablet has had poor sales. She may be marked down for her close involvement with the tepidly received Windows 8

Eric Rudder

PRO:A fixture in the background at Microsoft for two decades, this deeply tech-savvy exec now runs Microsoft’s long-term research unit and sets overall technical strategy. He is the nearest the company has to a big thinker in the mould of Bill Gates

CON: Never having been a business unit leader, he may not have the experience to deal with the sharp-elbowed internal politics of Microsoft to survive as CEO

Kevin Turner

PRO: Microsoft’s chief operating officer for the last eight years, the former Wal-Mart Stores exec is the power behind the company’s fearsome sales operation

CON: A professional salesman and motivator, he does not come from an engineering background, which could be a liability

Jeff Raikes

PRO: Bill Gates, who is on the panel to choose the next CEO, picked this former leader of the Office unit to be CEO of his philanthropic foundation. Raikes’ experience, understanding of Gates’ thinking and steady hand might be an effective combination

CON: Immersed in the world of philanthropy for five years, he may be out of touch with the latest technology trends. The same generation as Ballmer, his appointment might be seen as a continuation of the old guard

John Thompson

PRO: It is possible the man leading the committee to find a new CEO may end up being considered by it. The former IBM exec went on to be CEO of Symantec, giving him experience both of a large company reinventing itself and an understanding of the enterprise software market

CON: He joined Microsoft’s board last year and has no direct experience of managing the firm. He is CEO of the little-known cloud-computing firm Virtual Instruments