There's never a shortage of losers in the stock market. Let's take a closer look at five of this past week's biggest sinkers.


March 15

Weekly Loss







Spectrum Pharmaceuticals (NASDAQ:SPPI)



3D Systems (NYSE:DDD)



Cliffs Natural Resources (NYSE:CLF)



Source: Barron's.

VirnetX took a hit after a jury determined that the world's largest maker of routers didn't violate the Internet security software company's patents. Even though the move validated its patents, they apparently aren't as valuable as the bulls would like to believe.

Mobile marketer Velti tumbled after surprising investors with a sharp quarterly deficit. Velti's top-line outlook for both the current quarter and all of 2013 were also well shy of Wall Street targets.

Spectrum Pharmaceuticals lost its lab coat after hosing down the sales projections for its marquee drug. Spectrum's Fusilev is being challenged by the return of a generic alternative.

The sell-off at 3D Systems continues. Shares of the 2012 market darling have been sliding in recent weeks as investors reassess the long-term profit potential of 3-D printing. It didn't help matters that the company's CTO sold more than half of his stake this week.

Finally, we have Cliffs Natural Resources falling off a cliff after announcing plans to halt production at a Canadian iron ore pellet plant, given the high extraction costs at that particular location.