Last Week's Biggest Stock Movers: Mylan, Ocular Therapeutix

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.

Mylan (MYL) -- Up 21 percent last week

Getting hooked up was the secret to Mylan's success. The generic drug maker offered to buy rival Perrigo (PRGO) in a deal valued at roughly $29 billion. It's often just the company being acquired at a premium that moves higher, but the market likes the synergy that it sees here.

Adding Perrigo to Mylan's arsenal would create a company generating revenue north of $15 billion this year. It also would help diversify Mylan's generic pharmaceuticals stronghold, since Perrigo is also a big player in other niches, including animal health and infant formula.

General Electric (GE) -- Up 14 percent last week

GE shot higher on Friday after announcing that it's looking to unload its financial and real estate businesses in the next two years. This would leave the iconic conglomerate with just its industrial businesses, but the market's mesmerized with what GE should be able to fetch in unloading its other operations.

Taser International (TASR) -- Up 12 percent last week

Taser doesn't just make its namesake stun guns. It's also the company behind the Axon wearable cameras that are being worn by a growing number of police forces, and that's a market that once again heated up after footage was released of a South Carolina man who was fatally shot by an officer while fleeing from an altercation.

It's not just stateside police forces snapping up Axon cameras to make sure that any controversial incidents are recorded. Taser announced on Thursday that London was buying 178 of the Axon cameras, the company's first significant order in the United Kingdom.

Ocular Therapeutix (OCUL) -- Down 34 percent last week

%VIRTUAL-WSSCourseInline-799%Last week's biggest decliner was Ocular Therapeutix, which took a hit after announcing disappointing test results for a potential treatment for post-surgical ocular inflammation and pain. The late-stage trial was reasonably successful on the pain-tackling front, but its efficacy fell short in dealing with inflammation.

This is the "feast or famine" nature of upstarts. Stocks will be volatile for young biotech companies with a lot riding on a promising drug receiving regulatory approval to hit the market.

Extreme Networks (EXTR) -- Down 23 percent last week

Shares of the California-based provider of networking solutions crashed on Friday after it posted ugly preliminary quarterly results. Extreme Networks warned that revenue will fall well short of its earlier guidance. It will also be posting a larger deficit than its original forecast.

Extreme Networks blames the shortfall on customers in the higher-education market as well as stadium and venue deals pushing out orders after the end of the March quarter. This wouldn't be a problem if those sales materialize in the following quarter, but the market tends to be skeptical when key accounts are holding back on their spending.

Zynga (ZNGA) -- Down 10 percent last week

The company that put social gaming on the map with "FarmVille" and "Mafia Wars" took another step down last week after announcing that founder Mark Pincus would be replacing Don Matrrick as CEO. Mattrick replaced Pincus two years ago, and the market cheered the news at the time. Mattrick was heading up Microsoft's (MSFT) Xbox division, and that seemed like the right gaming pedigree to take Zynga to the next level.

Unfortuntely for Zynga, bookings never recovered from their 2012 peak. Folks on smartphones and social networking sites tend to tire quickly of games, forcing companies to stay on top by introducing new diversions. Perpetual reinvention isn't easy, and Zynga buckled. Naturally, the market isn't happy to see its former CEO come back, though Zynga was in a much better place when he left.

Motley Fool contributor Rick Munarriz has no position in any stocks mentioned. The Motley Fool owns shares of General Electric Company. 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.