Date: August 4, 2011
Dow: -512, down 4.3%
Congress was the source of so much disappointment during 2011. Legislators reached the pinnacle of ineptitude in early August, when they failed to meet a deadline to raise the debt ceiling. It happened one day before a monthly jobs report was expected, which made investors even more nervous. The number of economists forecasting a double-dip recession suddenly spiked, and the August 4 plunge was declared the worst trading day since the 2008 financial crisis.
The worst, that is, until the following Monday.
NEXT: S&P downgrades the U.S.