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

Sept. 16

Weekly Loss

My Watchlist

Perfect World (Nasdaq: PWRD) $14.18 (24%) Add
Netflix (Nasdaq: NFLX) $155.19 (24%) Add
Zillow (Nasdaq: Z) $29.19 (21%) Add
Research In Motion (Nasdaq: RIMM) $23.93 (19%) Add
Silvercorp (NYSE: SVM) $7.02 (17%) Add

Source: Barron's.

It wasn't perfect for Perfect World after the Chinese online gaming company lowered its guidance for the current quarter. In a move to prolong the life cycle of its current games, Perfect World is slowing in-game promotional activity. The rub here is that the company is now expecting revenue to dip sequentially.

Netflix turned into Not Flicks after lowering its domestic subscriber guidance. The video service is now expecting to close the third quarter -- which ends next week -- with just 24 million stateside accounts. During its second-quarter report, just two months ago, Netflix was banking on 25 million families of couch potatoes on its rolls.

Real estate website Zillow is one of the few IPOs this year that continues to trade above its IPO price. Zillow's stock is still comfortably above its $20 debut, but it continues to fall back after peaking at $60 on its first day of trading.

RIM took a hit after suffering the first year-over-year decline in BlackBerry shipments in the company's history. Its PlayBook tablet is also a dud, and the company is exploring price cuts before throwing in the towel on the once-promising tablet gadgetry.

Finally, we have Silvercorp slipping after an online report accused the company of misrepresenting the productivity of a Chinese silver mine. Every company has its critics, but this report was issued by the AlfredLittle.com blog, which earlier this summer also poked holes in Deer Consumer Products (Nasdaq: DEER). Silvercorp's stock did make back some of its earlier losses Thursday, after responding to the report and announcing a share buyback.

It was a rough week for these five stocks. Let's see if they bounce back.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.