Last week wasn't one for the bulls or bears. The markets proved generally yawn-worthy, with the Dow closing flat as the S&P 500 and Nasdaq notched losses of 0.3%. However, in any market, you'll always find sinking stocks.

Let's take a closer look at five of this past week's biggest disappointments:

Company

April 8 Weekly Loss My Watchlist
Puda Coal (NYSE: PUDA) $6.00 (51%) Add
American Superconductor (Nasdaq: AMSC) $13.77 (44%) Add
Duoyuan Global Water (NYSE: DGW) $3.22 (41%) Add
Meru Networks (Nasdaq: MERU) $15.66 (24%) Add
Ruby Tuesday (NYSE: RT) $10.63 (19%) Add

Source: Barron's.

China's Puda Coal was last week's biggest loser, shedding more than half of its value after a Business Insider article raised troubling allegations regarding improper share transactions by its chairman. Puda Coal, a promising provider of premium-grade cleaned coking coal to steel mills before the scandal, is reviewing the allegations. Business Insider took the article down over the weekend, so things will get interesting if Puda is vindicated in the matter.

American Superconductor got smacked down after its largest customer refused an order of wind turbine core electrical components and spare parts and has yet to pay for some of its previous orders. The news forced the company to talk down its guidance. American Superconductor now expects to post a loss for the current quarter.

Duoyuan Global Water got into hot water after its CFO stepped down and the water treatment equipment supplier's board formed a special committee to investigate allegations of improprieties.

Shares of Meru Networks took a hit after the provider of enterprise Wi-Fi gear posted disappointing preliminary quarterly results. Meru is now targeting $20 million to $20.5 million in revenue for the quarter that ended in March. That may not be a whole lot less than the earlier top-line guidance of $21.5 million to $22.5 million, but investors hate to see presumably conservative targets hosed down this late. The news was enough to send rival Aruba Networks (Nasdaq: ARUN) down in sympathy.

Finally, =Ruby Tuesday's fresh bread promotion led to less dough for investors. The casual dining chain had a crumb-y quarter, with comps and earnings clocking in lower. Wall Street was looking for bottom-line improvement.

These five stocks endured a rough week. Let's see which ones bounce back in the days ahead.

Which of these five stocks do you think bottomed out last week? Share your thoughts in the comment box below.

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Longtime Fool contributor Rick Munarriz enjoys cheering on winners and whispering words of encouragement to the losers. He does not own shares in any of the companies in this story. He is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Fool has a disclosure policy.