The S&P 500 index posts a "double sigma" surge, making it harder to earn "quick money" in the future.

```htmlGolden Ten Data reported on May 29 that the S&P 500 Index has returned to its all-time high, but there is no doubt that Wall Street’s stunning and fierce rally over the past two months has significantly slowed. The benchmark index soared over 19% from March’s low in just 41 trading days. Analysts at DataTrek Research described this rebound as approaching a "two sigma" level, meaning the gains have deviated by two standard deviations from any 100-day average return. This may indicate that the "fast money" has already been made; investors should prepare for a period of slower, choppy upward movement in the US market during the summer, or perhaps even range-bound trading. DataTrek analyst Jessica Rabe wrote in a report: "Historical experience suggests that the S&P Index may enter a consolidation phase here, with its pace of gains expected to slow down considerably."```