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.


Dec. 13

Weekly Loss

ImmunoCellular Therapeutics  (NYSE MKT:IMUC)



Violin Memory (NYSE:VMEM)



Triangle Petroleum (NYSEMKT:TPLM)



Gigamon (NYSE:GIMO)






Source: Barron's.

Let's start with ImmunoCellular Therapeutics. The biotech lost nearly two-thirds of its value as a once potentially promising cancer drug fell short in a clinical trial. The overall survival of patients with glioblastoma was not deemed to be statistically significant in the test during the second of three required clinical trial phases.

Violin Memory continued its autumn slide on reports that its chief technical officer is leaving the company. Class action lawsuits also continued to pile on during the week, following last month's brutal quarterly report at the maker of computer data storage products. Violin Memory's surprisingly large loss and weak guidance came in its first financial report as a public company. You don't get a second chance at making a first impression.

Triangle Petroleum was gushing losses after the energy explorer reported quarterly results. Triangle's profit of $0.18 a share fell short of the $0.24 analysts were targeting for the period.

Gigamon, the developer of data traffic management software, tumbled late in the week as D.A. Davidson analyst Mark Kelleher initiated coverage with a disappointing "neutral" rating. He argues that faster network connections should increase demand for Gigamon's offerings, but Kellerher's price target of $28 was nearly where the stock already was at the time.

Gogo soared 23% a week earlier after announcing certification for deploying its Ku-satellite technology in Boeing 747-400 aircraft. The move allows the in-flight Wi-Fi provider to make an international push. Gogo gave back roughly half of those gains this past week. There was legislation introduced in Congress to block voice calls -- something that could be seen as detrimental to the value of Gogo's airborne connectivity -- but the sell-off was probably more a case of profit-taking after the prior week's rally.  

Longtime Fool contributor Rick Munarriz and The Motley Fool have no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools don't 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.