Today's 3 Worst Stocks

A day after aluminum producer Alcoa kicked off earnings season Monday with a pleasantly surprising quarterly report, markets couldn't help extrapolating, and rose for a fourth straight session. The S&P 500 Index (SNPINDEX: ^GSPC  ) added 11 points, or 0.7%, ending at 1,652. Tomorrow, Wall Street will undoubtedly dissect the Federal Reserve minutes from June's meeting, which will be released at 2 p.m. ET. Despite the excitement over a new round of corporate earnings, the stocks on today's list crept stubbornly lower.

Intuitive Surgical (NASDAQ: ISRG  ) shareholders couldn't get too psyched about upcoming earnings for the simple fact that the company revealed that earnings would be terrible this quarter. The robotic medical equipment innovator decided to warn shareholders about their optimism late Monday, and shares subsequently plummeted 16.2%. The company thinks sales will increase just 6% in the second quarter, blaming stingy health insurers and a weak economy for the stagnant growth. 

Semiconductor manufacturer Micron Technology (NASDAQ: MU  ) saw shares crater 6.4% Tuesday, though there wasn't an obvious reason behind the exaggerated sell-off. This much is clear: Micron Technology lost more than $1 billion last fiscal year; the stock has more than doubled this calendar year alone, and shares are more than 80% more volatile than the broader market. Needless to say, this combination of characteristics can leave some room for a drop like today's.

Lastly, JDS Uniphase (NASDAQ: JDSU  ) shed 3.6% today. The company makes equipment that measures and tests the use of communications technology, and naturally many of its customers include players in the telecom business. Unfortunately for JDS shareholders, telecom was the worst-performing sector in the market today. Like Micron, shares are extraordinarily volatile -- they swing nearly three times more violently than the average stock -- so even a slight setback like today's sluggish telecom sector can cause chaotic price movements.

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