Why is the market sliding so hard, so fast?

Stock Market Opens After One Day After Dow Plunges Over 200 Points (Credit: Photo by Spencer Platt — Getty Images)

Why is the stock market sliding so fast? Why do the Wall Street mavens who were predicting big gains for 2014 suddenly look so wrong? In a day of elastic swings, though always in negative territory, the S&P shed 15 points on Wednesday. It’s the most recent leg in a series of sharp daily declines that have erased virtually all of the once-sumptuous market advance for 2014. On September 2, the S&P stood at an all-time high of 2017, handing investors near double-digit gains in just eight months. In a flash, the S&P has retraced a parabola that puts it back nearly to where it started. The Dow is faring even worse. Following its 173-point decline on Wednesday, the index has now dropped 2.6% from the start of 2014.