There's never a shortage of stocks going the wrong way in any given chunk of time. No stock goes straight up, and sometimes fundamentals can get a bit wobbly. Let's take a closer look at five of this past week's biggest sinkers.

Company

July 25

Weekly Loss

Silicom Ltd. (SILC -0.84%)

$27.24

26%

New Oriental Education (EDU 3.32%)

$19.40

20%

Xilinx (XLNX)

$41.46

13%

Kandi Technologies (KNDI 3.06%)

$17.38

11%

Core Labs (CLB)

$147.22

11%

Source: Barron's.

Let's start with Silicom, which posted a quarterly profit of $0.50 a share, sorely missing the $0.58 the pros were forecasting. Needham downgraded Silicom after the uninspiring report, in which revenue declined sequentially as Silicom warned of soft demand that it expects to continue in the near term.

New Oriental Education also fell victim to head-shaking analysts after offering up ho-hum guidance. The Chinese provider of tutoring services warned that it expects revenue for the current quarter to climb 6% to 10%. Even at the high end of its guidance, it's roughly half as much octane as Wall Street was projecting. Morgan Stanley and JPMorgan Chase stuck to their bullish ratings but lowered their price targets after the report. 

Xilinx tumbled after posting disappointing quarterly results. Its revenue of $612.6 million fell well short of Wall Street's $631 million target. Its guidance, suggesting that revenue growth will be flat to slightly lower sequentially, was also a letdown. A couple of analysts moved to downgrade Xilinx on the report, but Argus did buck the trend by upgrading the stock a day after the carnage. 

Kandi Technologies moved lower after a strong rally earlier this month. The Chinese maker of electric vehicles initially moved higher on Monday on reports that a generous sales-tax break -- going into effect in September to encourage China to embrace more emissions-free forms of transportation -- would apply only to China-made cars. That would give Kandi and China's homegrown players a competitive advantage. Spirits soured later in the week, though, when a Seeking Alpha piece called into question Kandi's latest financial filing. Despite the setback, the stock is still trading higher than it was two weeks ago, and it has more than doubled since the end of November. 

Finally, we have Core Labs getting cored after putting out an uninspiring quarter. Even Jim Cramer wasn't impressed.

"That last quarter was really bad," Cramer said on CNBC's Mad Money. "I need to see the next quarter before I get back on board."