Microsoft Corp struck a $7 billion deal to acquire Nokia Corp's struggling cellphone business, a bold move to try to catch up in a fast-growing mobile market that is now dominated by Samsung Electronics and Apple.

The deal comes on the heels of Microsoft's announcement that chief executive Steve Ballmer will retire as soon as a successor is found. As part of the deal for Nokia's devices and services business, Microsoft will bring aboard 32,000 Nokia employees including CEO Stephen Elop, who is believed to be among the contenders for Ballmer's job.