Traders Are Blaming Today's Sell-Off On 7 Things

Today's 400-point plunge in the Dow has investors a bit freaked out.

So what's behind the sell-off?

Rich Barry, an NYSE floor governor, identified seven catalysts in an email he just blasted from the New York Stock Exchange floor:

1- A shockingly weak Retail Sales report that hit the tape at 8:30 AM ET. (Expect Q3 GDP growth to be revised downward.)

2- News that the $54 Billion Shire-Abbvie deal was falling apart also weighed on stocks.

3- A September drop in PPI that had trading desks mentioning the dirty 'D' word. (Deflation concerns -- see the price of oil.)

4- A report on October manufacturing activity in New York that was poor too, slowing worse-than-expected after posting its strongest pace in nearly five years last month.

5- A second hospital worker contracted Ebola and flew in a plane recently.

6- The stock market in Greece came close to a full-blown crash.

7- ISIS

This isn't intended to be an exhaustive list. But it pretty much addresses every category of risk: economic slowdown, corporate profit slowdown, falling prices, geopolitical turmoil, and unknown unknowns like Ebola.