Nokia has announced that Olli-Pekka Kallasvuo is out as CEO and that he has been replaced with a top executive from Microsoft. That executive is Stephen Elop who was formerly part of Microsoft's Business Division. Elop will take over as CEO of Nokia on September 21.

Microsoft CEO Steve Ballmer sent an email to Microsoft workers notifying them of the change and stating that, "Stephen leaves in place a strong business and technical leadership team, including Chris Capossela, Kurt DelBene, Amy Hood and Kirill Tatarinov, all of whom will report to me for the interim." Ballmer also pointed out that the Business Division has continued to grow with a 15% growth rate in the previous quarter.

The Associated Press reports that news of Kallasvuo's replacement has sent stock in Nokia up 5% in Helsinki. Elop was also a top executive at other notable tech firms like Juniper Networks, Adobe Systems, and Macromedia.

Nokia board chairman Jorma Ollila said in a statement, "The time is right to accelerate the company's renewal — to bring in new executive leadership with different skills and strengths in order to drive company success."

Kallasvuo will also give up his seat on the board at Nokia immediately and will be replaced there by Elop. Kallasvuo has been with Nokia since 1982 and he will continue to chair the board of the Nokia Siemens Networks unit as a non-executive.

Nokia holds the majority of the handset sales globally with 33% of the market, but the company has a history of missing trends that have kept it from competing in high-end smartphone markets where profits are higher.

The departure of Kallasvuo is no surprise; Nokia has been actively looking for a new CEO since July. Perhaps the biggest factor contributing to the ouster of Kallasvuo was the fact that he has been unable to grow business in North America, Nokia's poorest performing market. When Kallasvuo took over as CEO in 2006 he vowed to make North America a priority.