Microsoft CEO Steve Ballmer listens to question during keynote address in San Jose
Microsoft CEO Steve Ballmer, in the post since 2000, has announced he will retire in the next 12 months. Reuters

Steve Ballmer announced today that he will step down as CEO of Microsoft (NASDAQ:MSFT) sometime in the next 12 months, as the company attempts to unify its products and services under the "One Microsoft" banner. The move apparently went over well with investors. Microsoft shares rose nearly 6 percent in mid-morning trading to $34.50.

In an email to employees published by Microsoft, Ballmer said that his original plan to retire later would have caused a distracting transition in the middle of the company's realignment.

Ballmer, chief executive since 2000, said that Microsoft needs "a CEO who will be here longer term for this new direction," as the company attempts its "transformation." The full text of his email to employees is embedded below.

"I am writing to let you know that I will retire as CEO of Microsoft within the next 12 months, after a successor is chosen. There is never a perfect time for this type of transition, but now is the right time. My original thoughts on timing would have had my retirement happen in the middle of our transformation to a devices and services company focused on empowering customers in the activities they value most. We need a CEO who will be here longer term for this new direction. You can read the press release on Microsoft News Center.

This is a time of important transformation for Microsoft. Our new Senior Leadership team is amazing. The strategy we have generated is first class. Our new organization, which is centered on functions and engineering areas, is right for the opportunities and challenges ahead.

Microsoft is an amazing place. I love this company. I love the way we helped invent and popularize computing and the PC. I love the bigness and boldness of our bets. I love our people and their talent and our willingness to accept and embrace their range of capabilities, including their quirks. I love the way we embrace and work with other companies to change the world and succeed together. I love the breadth and diversity of our customers, from consumer to enterprise, across industries, countries and people of all backgrounds and age groups.

I am proud of what we have achieved. We have grown from $7.5 million to nearly $78 billion since I joined Microsoft, and we have grown from employing just over 30 people to almost 100,000. I feel good about playing a role in that success and having committed 100 percent emotionally all the way. We have more than 1 billion users and earn a great profit for our shareholders. We have delivered more profit and cash return to shareholders than virtually any other company in history.

I am excited by our mission of empowering the world and believe in our future success. I cherish my Microsoft ownership and look forward to continuing as one of Microsoft’s largest owners.

This is an emotional and difficult thing for me to do. I take this step in the best interests of the company I love; it is the thing outside of my family and closest friends that matters to me most.

Microsoft has all its best days ahead. Know you are part of the best team in the industry and have the right technology assets. We cannot and will not miss a beat in these transitions. I am focused and driving hard and know I can count on all of you to do the same. Let’s do ourselves proud.

Steve