The bull run in Microsoft's stock this past year has helped the tech giant surpass Exxon Mobil and seize the rank of the second-most-valuable company, behind Apple Inc. Under new CEO Satya Nadella, Microsoft has worked to overcome its reputation as a clumsy behemoth struggling to keep up with new tech trends and consumer habits. Nadella has cut expenses - and jobs - while pledging to refocus the company on mobile technology and cloud computing.