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.

Company

May 24

Weekly Loss

National Bank of Greece (NBG.DL)

$1.22

49%

Cirrus Logic (CRUS -0.65%)

$17.36

22%

Whiting USA Trust (NYSE: WHX)

$5.05

19%

Halcon Resources (HK)

$5.54

11%

Newcastle Investment (DS -5.69%)

$5.27

11%

Source: Barron's.

Let's start with National Bank of Greece. Greece's largest bank shed nearly half of its value ahead of reasonable quarterly results, while its thriving Turkish unit helped steer the financial services provider to a rare profit. The shares were halted on Friday as the bank prepares to complete a recapitalization plan in the coming days.

Cirrus Logic took a logical hit after warning that its margins will be contracting. Speaking at an investor conference, Cirrus Logic's CEO warned that the cutthroat nature of smartphone component providers will drop the company's gross margins from north of 50% today to mid-40% in the future as pricing pressures kick in.

Whiting USA Trust tumbled a week after going ex-dividend. It's not necessarily surprising to see investors move on a week after a high-yielding trust shells out a quarterly distribution. Whiting's units decreased in value 13% a week earlier, and half of that was in the form of the trust's payout. It's also not a shock to see Whiting in a perpetual state of decline. The units are backed by depleting assets, and the trust will terminate once a set amount of oil and gas has been sold. However, the 19% plunge is unusual even for a company that has already gone through 77% of its production rights and will probably terminate in two years.

Halcon Resources tumbled on Thursday shortly after providing a poorly received operation update on the production of its acreage in northeast Ohio and northwest Pennsylvania. Halcon expects decent natural gas production, but the drilling for oil hasn't proved as lucrative.

Finally, we have Newcastle taking a hit after an analyst downgrade. Keefe Bruyette downgraded its rating on the stock from "outperform" to "market perform." Newcastle is a real estate financing specialist that is now trading even more below its book value, which stood at $7.07 a share as of the end of March.

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