Today the SPX was down 0.60%. Price retraced 50% from the low hit today, as compared to Friday's close, by looking at the intra-day chart.
The SPX logged a Doji candle on Thursday, which usually shows indecision. Given the next day was a down day, the reversal was cemented.
Today the SPX logged a bearish hangman. This, along with the previous doji, confirms that the trend is reversing.
Target 2190.