The Dow was down 343.7 points and the Nasdaq shed 90 on a day that started out all sunshine and roses.

For a couple of days, the economic news wasn't quite as bad as it could have been, or maybe some of the numbers actually were a little better or beat the numbers, and I think there was some idea that, hey, maybe the economy is not as bad as some people had feared, but then reality reared its ugly head at 10 a.m. when we got the ISM Manufacturing numbers."

US manufacturing dove to a 10-year low. The ISM index of national factory activity dropped 1.3 points to 47.8 in September. That was the lowest number since June 2009 – as the US economy was emerging from the Great Recession. A reading below 50 signals manufacturing is contracting. The weak September number follows on the heels of a 49.1 print in August. Analysts had expected a bounce-back to 50.