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Twenty-eight years ago, the Dow Jones industrial average plunged 23 percent in what remains the largest one-day loss in U.S. stock market history.
The exact cause of "Black Monday" has never been determined, so it is difficult to say whether conditions are developing for a repeat of history.
The Federal Reserve partly blames international volatility spreading to U.S. shores as well as the use of a new product from Wall Street called "portfolio insurance."
Many point to China's stock market crash this summer as reason to worry about another cataclysmic event occurring soon.
Crash-like fear was certainly in the air Monday, Aug. 24, of this year when the Dow fell more than 1,000 points on an intraday basis before recovering.
A week ago, CNBC Pro pointed out how an indicator that's supposed to signal a "Black Swan" moment is at its highest level ever.
And Carl Icahn, arguably the best investor during this bull market, said at the end of last month that there was a "looming catastrophe" ahead because of the Federal Reserve's low-rate policy.
So what else has investors frightened that a violent drop in stocks may occur before the end of the year?