Let's go over some of last week's best and worst performers.
NeuroDerm (NDRM) -- Up 99 percent last week
The market's biggest gainer, by far, was NeuroDerm. Shares of the small biotech nearly doubled after it announced encouraging results on a clinical trial taking place with its promising treatment for Parkinson's disease.
Israeli-based NeuroDerm revealed that a high-dose version of its treatment has had a welcome effect on patients who would normally have to resort to surgery. It's still early in the process, but it's a pretty big deal for a company that even after last week's pop is still valued at a little more than $200 million.
Cnova (CNV) -- Up 17 percent last week
Analysts warmed up to Cnova last week. Deutsche Bank (DB) and Bank of America Merrill Lynch (BAC) initiated coverage of the Dutch e-tailer with bullish ratings. The two firms may be biased, though: They helped take Cnova public two months ago.
Cnova has 12.9 million active customers, largely in Europe and Latin America. It went public at $7, but the new price targets are as high as $11.
American Realty Capital Properties (ARCP) -- Up 17 percent last week
Shares of American Realty Capital Properties moved higher after Corvex Management revealed that it has taken a 7.1 percent stake in the real estate investment trust specializing in stand-alone commercial properties.
Corvex is an activist investment fund. It doesn't like to stand still, but it remains to be seen how it's planning to shake things up here.
Civeo (CVEO) -- Down 52 percent last week
Last week's biggest sinker was Civeo. The provider of site-specific housing for oil workers shed more than half of its value after painting a bleak prognosis of its near-term performance. Civeo will be dramatically scaling back its operations, and it's also suspending its once-hefty quarterly dividend.
Weight Watchers (WTW) -- Down 19 percent last week
The leading provider of weight management services shed some weight of its own last week. Weight Watchers is in the process of repositioning its brand, and last week announced changes to its Weight Watchers Magazine that didn't sway skeptics.
Weight Watchers is in a funk as calorie counters turn to apps and other cheaper alternatives. Analysts predict that revenue slid 14% in 2014 with profitability taking an even bigger hit. They see more declines on both ends of the income statement in 2015.
Jinpan International (JST) -- Down 14 percent last week
The maker of cast resin transformers took a hit after nixing plans to take itself private. Jinpan had announced in late September that it was going to go private, but last week revealed that the insider-backed buyout proposal was not going to happen.
Motley Fool contributor Rick Munarriz has no position in any stocks mentioned. The Motley Fool recommends Jinpan International Limited. Try any of our Foolish newsletter services free for 30 days. Check out our free report on one great stock to buy for 2015 and beyond.