Though the market closed out the month of April on a strong week, it still had room for plenty of losing stocks. Let's take a closer look at five of this past week's biggest sinkers:

Company

May 20 Weekly Loss My Watchlist
SMART Technologies (Nasdaq: SMT) $7.06 (28%) Add
Country Style Cooking (NYSE: CCSC) $12.42 (27%) Add
Quantum Fuel Systems (Nasdaq: QTWW) $3.79 (26%) Add
TravelCenters of America (AMEX: TA) $5.86 (26%) Add
Yongye International (Nasdaq: YONG) $3.72 (22%) Add

Source: Barron's.

SMART shares got wiped clean after the maker of digital whiteboards flunked out in its latest quarter. SMART barely managed a profit, though analysts banked on earnings of $0.08 a share. Whiteboards are obvious classroom upgrades, but cash-strapped schools probably won't make any such high-tech upgrades until their budgetary storm clouds pass.

Country Style Cooking Restaurant Chain was sent back to the kitchen after posting disappointing quarterly results. Margins shrank as costs grew out of control for the China-based eatery. Is CSC's management up to the task of growing the 140-unit chain in a cost-effective manner? The Sichuan cuisine specialist announced last week that it was bringing on a former head of training and operational development for North Asia from McDonald's (NYSE: MCD).

Easy come, easy go for Quantum. Shares of Quantum nearly doubled two weeks ago after the company demoed a plug-in hybrid version of the popular F-150 pickup truck during a clean transportation expo earlier this month. Last week, it gave back some of those gains, though the stock still sits well above where it was two weeks ago.

TravelCenters of America blew a tire after proposing a secondary stock offering. Companies issue freshly minted stock all of the time, but TravelCenters of America's proposed 10 million-share offering is a big chunk of new equity for a company with less than 20 million shares currently outstanding.

Investors dumped shares of Yongye after the Chinese fertilizer specialist got smeared in an analyst report. Absaroka Capital claims that Yongye's a fraud, taking the company to task for its acquisitions, product claims, and management compensation. Despite Absaroka's relative obscurity, negative comments on small Chinese companies have been enough to shoo away believers in the past.

After these five stocks' 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.

The Motley Fool owns shares of Yongye International. Motley Fool newsletter services have recommended Yongye International, Country Style Cooking, and McDonald's. Try any of our Foolish newsletter services free for 30 days. We Fools may not 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.

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, except for CSC. He is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early.