Last Week's Biggest Stock Movers: Deals Lift Dish

Plenty of stocks go up and down in any given week. The gainers inspire us to keep investing. The decliners keep greed in check while reminding us about the risks of the equity markets.

Let's go over some of last week's best and worst performers.

Celldex Therapeutics (CLDX) -- Up 47 percent last week

%VIRTUAL-WSSCourseInline-630%Shares of Celldex soared last week after the company revealed encouraging clinical study information. Celldex's treatment for a rare brain cancer halted the aggressive cancer's progression in nine of 33 patients. That may not seem like much of a success rate, but it's a big deal for this type of tumor. Biotechs are volatile, especially when there's a lot riding on a single treatment.

DISH Network (DISH) -- Up 14 percent last week

The country's second-largest satellite television provider moved higher on a couple of compelling developments. The first catalyst was the government raising $16.4 billion in an auction for radio spectrum airwaves that should boost the value of DISH's own wireless license. Then it arrived at a temporary extension with CBS (CBS), buying the two companies more time to negotiate a carriage rights deal and averting a blackout in which DISH customers would've been without CBS channels.

LeapFrog Enterprises (LF) -- Up 11 percent last week

The holiday season is going to be critical for LeapFrog, and the maker of electronic learning toys is generating plenty of buzz and critical acclaim. LeapFrog's toys had a big week, winning Oppenheim Toy Portfolio awards, Silver Awards at the National Parenting Publication Awards presentation, and Dr. Toy's "2014 Best Toys" distinctions

LeapFrog had better hope that some of the industry praise carries over into sales this holiday season. Sales have been declining sharply in recent quarters.

El Pollo Loco (LOCO) -- Down 18 percent last week

One of this year's hottest restaurant IPOs has been cooling off since reporting earnings earlier this month. El Pollo Loco -- a quick-service chain specializing in citrus-marinated chicken -- took another hit this week after announcing a secondary offering.

El Pollo Loco had to price the 6 million shares in the offering at $27, well below where the stock was just before the secondary was announced. This won't be dilutive. All of the shares being offered are by pre-IPO investors. El Pollo Loco isn't receiving any proceeds from the secondary, but it's not an encouraging sign to see so many insiders cashing out.

El Pollo Loco's stock has fallen in 10 of the 11 trading days since posting quarterly results on Nov. 6.

Renren (RENN) -- Down 16 percent last week

The market bought into the Renren hype when it went public a few years ago. The Chinese social networking website was supposed to be the Facebook (FB) of China. It hasn't played out that way. The stock took a big hit on Friday after the company announced awful quarterly results.

Revenue plunged 47 percent to $21.6 million, and Renren's operating losses continue to widen. It won't be getting any prettier anytime soon. Renren's outlook calls for just $15 million to $17 million in revenue during the fourth quarter. The once-promising company is in a state of flux. It has divested its video business and is streamlining its fading gaming business. It's down to offering college financing for Chinese students in an effort to cash in on its thinning user base. Some have joked that Renren is the MySpace of China now, but Renren is still backed by a cash-rich balance sheet that will afford it at least a few more years to get it right.

GameStop (GME) -- Down 15 percent last week

Investors may be hunting down cheat codes after video game retailer GameStop posted uninspiring financial results. GameStop fell short of initial sales targets, blaming the delay of a single video game for its misfortune. However, GameStop's problems go beyond a single game.

It's having no problem selling Xbox One and PS4 consoles. It's also holding up reasonably well with its pre-owned business. The challenge for GameStop is that folks just aren't buying new games there. Software sales are going digital. GameStop's taken steps to tackle the trend, but it's not enough.

Motley Fool contributor Rick Munarriz has no position in any stocks mentioned. The Motley Fool recommends Celldex Therapeutics, Facebook and LeapFrog Enterprises. The Motley Fool owns shares of Facebook, GameStop and LeapFrog Enterprises. Try any of our Foolish newsletter services free for 30 days. Want to make 2015 a winning investing year? Check out The Motley Fool's one great stock to buy for 2015 and beyond.