The S&P 500 started with a surge higher, then reversed and closed at the lows of the day. In the initial surge, the S&P made a new all-time high before the reversal took place. If you are a chart technician, the candlestick formation is called a topping tail. In a 'normal' stock market this signals a top and likely reversal. However in this market, no investors will believe it. The current stock market is one of 'buy-the-dip'. Every dip has been bought, every short crushed.
Could the fact that no investors believe the topping tail will be a top, actually mean it is the top? We will know tomorrow. For it to confirm you need a strong down move of over 10 points on the S&P 500. Even then, most won't believe it, but I will.