Before revision:  Up to 23\% of observed trades may have contributed the the measured inefficiencies , leading to a ROC greater than 2 billion USD. A subset of the constituents of the S&P 500 index experience the greatest amount of ROC and may drive inefficiencies in other stocks.
After revision:  However, these dislocations do not occur uniformly throughout the trading day. We identify a characteristic structure that features more dislocations near the open and close. Additionally, around 23\% of observed trades may have contributed the the measured inefficiencies , leading to a ROC greater than 2 billion USD. A subset of the constituents of the S&P 500 index experience the greatest amount of ROC and may drive inefficiencies in other stocks.