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

April 5 Weekly Loss My Watchlist
Polycom (Nasdaq: PLCM) $14.56 (24%) Add
Groupon (Nasdaq: GRPN) $14.18 (23%) Add
Millennial Media (NYSE: MM) $18.42 (22%) Add
Hovnanian (NYSE: HOV) $2.02 (18%) Add
ReneSola (NYSE: SOL) $1.89 (18%) Add

Source: Barron's.

Polycom wasn't a pretty picture after the corporate videoconferencing company warned that it would miss its quarterly forecast for the period ending last month. Weakness is prompting Polycom to slash its revenue guidance by 8%. Its preliminary quarterly profit of $0.22 a share falls well shy of the $0.30 a share that analysts were expecting.

Groupon took a hit after warning that it had overstated its fourth-quarter results. Refunds are apparently being requested at an alarming clip through the daily deals leader.

Millennial Media had the best initial trading pop for an IPO in nearly a year when it went public two weeks ago. This past week found investors kicking in with buyer's remorse when it came to the mobile advertising speedster.

Hovnanian saw its foundation crumble a bit after completing a secondary offering. The struggling homebuilder is printing 25 million new shares, but had to settle for $2 a share on the pricing. How low and desperate is that? Well, even after the stock's nearly 18% drop last week it still closed just barely above the $2 price.

Finally, we have ReneSola shining less brightly for investors. There was no company-specific news on ReneSola, but solar energy companies have been out of favor in recent months.

ReneSola's stock initially moved higher after it posted mixed results last month, but there's something brutally wrong when a company checks in with a gross margin of -23.1%, and that's even before considering a nasty inventory writedown.

Ready for a bounce
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Motley Fool newsletter services have recommended buying shares of Polycom. The Motley Fool has a disclosure policy. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. Try any of our Foolish newsletter services free for 30 days.

Longtime Fool contributor Rick Munarriz calls them as he sees them. He does not own shares in any of the stocks in this story. Rick is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early.