5 reasons stocks are tumbling now

  • Specialist trader Ned Zelles works at his post on the floor of the New York Stock Exchange. REUTERS/Brendan McDermid

    NEW YORK - Well, that was fun while it lasted.

    For years, investors in U.S. stocks shrugged off threats -- a government shutdown, fear of a euro collapse, a near U.S. debt default - and just kept on buying. At the sixth anniversary of the bull market in March, the Standard and Poor's 500 index had more than tripled in value.

    Now, buyers are hard to find. A wave of selling has hammered major indexes, with the S&P 500 losing nearly 6 percent last week. That was its worst weekly slump since 2011. U.S. stock futures Monday are indicating another steep decline that could pull the index into what Wall Street calls a "correction," or a fall of 10 percent from a recent high.

    Corrections are natural in a bull market, a pause in the market's march higher, and this one is long overdue. They usually come about once every 18 months. The last one was four years ago.

    The big trigger for selling last week was yet more evidence of a slowdown in China's economy, but there were plenty of other worrisome developments weighing on the market.

    Click ahead for a look at a few of them, and why you may not want to panic, yet.