5 of Last Week's Biggest Losers

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.

Source: Barron's.

Affymax shed more than half of its value after announcing massive layoffs. Investors sometimes rally behind a company handing out pink slips as a cost-saving move, but the drugmaker's call to eliminate 75% of its workforce is as desperate as its warning that it may have to declare bankruptcy.

Dex One slipped after filing for Chapter 11 bankruptcy reorganization in a move to pave the way for the provider of local marketing solutions to merge with SuperMedia. It also posted quarterly results showing a 14% drop in ad sales.

TIBCO Software fell on Friday after posting quarterly results that were a little light on the top line. The enterprise software solutions provider also issued weak guidance for the current quarter.

Rentech Nitrogen Partners slipped after falling short of Wall Street's profit targets. Analysts were betting on net income of $0.55 a unit out of the high-yielding partnership producing nitrogen fertilizer. Rentech mustered earnings of only $0.51 a unit. Its guidance for 2013 also wasn't very inspiring.

Amarin closed lower every single trading day this past week. Chardan Capital Markets initiated coverage of the heavily traded fat fighter with a disappointingly cautious Hold rating.