Income tax expense: $5.30 billion
Earnings before taxes: $21.90 billion
Revenue: $104.51 billion
1-yr. share price change: 7.57%
Industry: IT consulting
International Business Machines (IBM), by most measures, is the second largest technology company in the United States, just behind Hewlett-Packard (HPQ). However, there are significant differences between the two. Most notably, HP is falling apart, while IBM's continued success, most recently under its first female CEO, Ginni Rometty, has landed it on this list. One critical reason for IBM's health is that it operates in a broad array of businesses, which means it doesn't need to rely on a single sector of the tech world. While IBM may be most associated with hardware and its long line of mainframes, its software operations and IT services division are just as large. IBM is also geographically diversified, and large fractions of its sales come from Europe and Asia.