Cooling down on the first day of April trading after a blistering hot beginning to the year, the S&P 500 Index (^GSPC 0.16%) lost about 0.5% on Monday. The benchmark is still up more than 9.5% in 2013, though you'd never guess it by glancing at today's three worst stocks. 

Taking a step back to look at the broader market trends, you simply do not want to be in technology today. Taking a step forward to carefully survey the damage, you absolutely do not want to be in the chip making business today. Micron Technology (MU 2.91%) led all laggards in the S&P, slipping 6% Monday. Granted, Micron stock is 70% more volatile than the overall market, so you'd expect it to take a larger-than-average hit on a bearish day like today. And when the stock's already posted nearly 50% gains this calendar year, some profit-taking in the second quarter isn't the most surprising thing in the world. 

But with fellow semiconductor manufacturer Advanced Micro Devices (AMD -0.31%) also selling off to the tune of 4.4% today, you've got to scratch your head and consider that there may be a shared catalyst driving both stocks lower. And there is: ISM manufacturing data in the U.S. and China both came in lower than expected, introducing fresh worries about the state of global industry. Not only that, but an electronics manufacturer in the ISM survey voiced doubts about the sector's health in the first half of 2013.

Lastly, Apple (AAPL -0.69%) shares tanked 3.1% to continue what has been an abysmal few months of trading for the iPhone maker. The ISM data from China weighs especially hard on companies like Apple with a large presence in the Asian markets. In fact, China -- as Apple's fastest growing international market -- is so crucial to the company's future that Apple changed its warranty policy for iPhones after the Communist Party's newspaper complained about how dishonest and unfair the warranty policy was.

Acutely aware of this perceived injustice, the newspaper still has trouble grasping the concept of "irony."