Stocks tumbled in late trading today, and the S&P 500 Index (SNPINDEX:^GSPC) was no exception. Cratering 23 points, or 1.4% today to close at 1,630, the S&P was still able to eke out gains in May, registering a seventh-straight month of advances, the longest winning streak since markets started rebounding in 2009. Today's broad market declines, however, were still outdone by the severe drops in today's three laggards.

Filtration systems producer Pall (NYSE:PLL) leads off today's list, having slumped 5.1%. The company reported quarterly results after the markets closed yesterday, and investors were underwhelmed. Sales didn't live up to expectations, although earnings actually beat estimates. The company's outlook really stung shares: Pall said that European expansion was going well, while operations in China were sluggish. Apart from that being the inverse version of what Wall Street wanted to hear, the company also lowered guidance for the fiscal year.

Shares in SAIC (NYSE:SAI) fell 4.9% Friday, the last full day of trading before Monday's quarterly report. Shareholders panicked today ahead of the announcement; analysts are calling for earnings to slide nearly 25% from year-ago levels, while revenue is projected to fall by 7%. However, it appears today's fall has more to do with the broad sell-off on Wall Street than the company itself; shares were up more than 3% after hours.

Lastly, biotech Amgen (NASDAQ:AMGN) slipped 4.5% today, as the health-care sector ended as the worst performing area of the markets Friday. As fellow Fool contributor Maxx Chatsko points out, Amgen is due to be coming up against competition from generic drugs in upcoming years for some of its most successful products as the remedies come off patent.

Fool contributor John Divine has no position in any stocks mentioned. You can follow him on Twitter @divinebizkid and on Motley Fool CAPS @TMFDivine.

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