Comment by bluedevil2k

Look at the ETF RSP yesterday. It's pretty much an S&P 500 index fund. When the S&P was down about 5% in the morning, RSP was down up to 40%. Didn't make any sense. Trading was getting halted every few minutes and buy orders were going unfilled.

http://finance.yahoo.com/echarts?s=RSP+Interactive#{%22range...