• Ticker: IBM
• YTD stock performance: -5%
• Fortune 500 rank: 20

IBM has been feeling the big blues pretty much all year. The stock is the worst performer in the Dow Jones industrial average in 2013.

The century-old tech giant is shifting further away from low-margin hardware to the more profitable software and services business, most importantly cloud computing.

But so far, the transformation has been rocky. In October, IBM (IBM) reported its sixth consecutive quarter of declining revenue, and missed sales forecast by over $1 billion.

Wall Street isn't too optimistic that IBM will quickly get back on track. Only 28% of analysts have a "buy" rating on the stock, the lowest percentage in at least two decades according to FactSet. And hedge fund titan Stan Druckenmiller recently revealed that he is shorting IBM.

But IBM has at least one big investor on its side. Warren Buffett, who made an $11 billion investment in IBM in 2011, remains the company's largest shareholder. --Hibah Yousuf

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