Should the SPX rally on Tuesday and beyond, the potential Fibonacci retracement targets taken from February’s high to Monday’s low are shown on the following monthly chart.
A drop and hold below the low could spark a catastrophic selloff to longer-term Fib retracement levels at 2030, or even 1700.
Note that there is a convergence zone of Fib levels and a trendline apex from 2650 to 2790, say 2750ish, making it an attractive eventual target for buyers in this extremely large 1200-point trading range.