There's never a shortage of losers in the stock market. Let's take a closer look at five of this past week's biggest sinkers.

Company

Dec. 28

Weekly Loss

My Watchlist

Alexza Pharmaceuticals (NASDAQ:ALXA)

$4.88

16%

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Marvell Technology (NASDAQ:MRVL)

$7.17

14%

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Vringo (NASDAQ:VRNG)

$2.66

13%

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Advanced Micro Devices (NASDAQ:AMD)

$2.28

12%

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American Superconductor (NASDAQ:AMSC)

$5.01

11%

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Source: Barron's.

Alexza Pharmaceuticals stumbled despite receiving FDA approval for its inhaled antipsychotic drug. People could be selling on the news, or they may be unhappy that the company doesn't plan to roll out the drug until the second half of next year.

Marvell Technology fell after Carnegie Mellon University was awarded $1.17 billion in a patent infringement case against the company. The lawsuit, initiated in 2009, argued that Marvell was infringing on a university patent for the way technology is used in reading data from high-speed magnetic disks.

There was no negative news to drive Vringo lower last week, but we can always attribute the move to this year's unique tax-gain selling phenomenon. Shares of Vringo have nearly tripled this year following some revenue-generating judgments related to some old Lycos patents it acquired earlier this year. Investors sensing that tax rates on capital gains will spike higher next year could have cashed out now to take advantage of favorable long-term rates that are set to expire this month.

Advanced Micro Devices failed to compute after the troubled chipmaker lost a longtime executive. Michael Goddard, corporate VP for product design engineering and chief engineer on client products, is leaving AMD for the greener pastures of Samsung.

American Superconductor shares dropped every trading day this past week. The provider of wind and power grid products and services swapped out a promissory note for a dilutive convertible note at the end of the prior week.

Longtime Fool contributor Rick Aristotle Munarriz and The Motley Fool have no positions in the stocks mentioned above. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.