S&P 500 wipes out 2.4% loss in biggest stock reversal since July 1991

It was a stock reversal for the ages: A near-uniform plunge followed by an everything rally made for a dizzying day on Wall Street.
 

The S&P 500 wiped out a 2.4% loss, marking the first time since July that it reversed a decline of 2%, and closed a whopping 2.6% higher. The initial rush to sell, followed by a dash to buy, was best illustrated by the second-to-second readings on share moves. The so-called Tick index, which compares the number of equities rising versus those falling in any moment, hit minus 1,900 before surging past 1,900. 

Never before has the