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

Jan. 20 Weekly Loss My Watchlist
Columbia Labs (Nasdaq: CBRX) $1.58 (34%) Add
North American Palladium (AMEX: PAL) $2.34 (24%) Add
Achillion Pharmaceuticals (Nasdaq: ACHN) $9.47 (23%) Add
Kinross Gold (NYSE: KGC) $10.21 (19%) Add
Complete Genomics (Nasdaq: GNOM) $2.39 (16%) Add

Source: Barron's.

Columbia Labs was the market's biggest loser, shedding more than a third of its value. The FDA advisory committee decided not to recommend the approval of Columbia's vaginal gel in reducing the risk of preterm birth.

North American Palladium slipped after the palladium and gold producer issued uninspiring guidance. The company will also be suspending operations at its Sleeping Giant mine.

Achillion called in sick after an article blasted the prospects of the company's experimental hepatitis C drug.

Kinross Gold wasn't shining after the miner revealed that construction of its Tasiast mine in Africa would be delayed for six to nine months.

Complete Genomics was one of the prior week's biggest losers after an Oppenheimer analyst downgrade. The genetics specialist continued its slide into last week.

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