Elliott Wave Analysis of the S&P-500 (SPX) from Sid at ElliottWavePredictions.com. Click on the chart twice to enlarge.
Wave 3 blue will reach 1.618 times the length wave 1 blue traveled at 1338.5. If wave 3 blue continues past that point, the next most likely relationship will be 2.618, which would take wave 3 blue all the way down to 1309.
There is an outside chance that today’s sell-off is just wave b (pink) of an expanded or running flat for wave 2 (blue), but movement below 1394 has reduced that possibility substantially.