Let me be the first to state I am not an expert (or even close) on Elliott Waves. But I understand the basics, and I recognize that the S&P 500 Index is in a nearly textbook perfect Elliott formation (headed to the downside).
By way of reference, check out this primer, then look at the graph above which I've annotated. I've put a small green highlight on the trendline (which extends back to the beginning of this entire rally) that, if broken, spells doom for the S&P. Added to which, the Elliott wave "C" seems to have started, which should take the index lower.
As always, these are just my opinions, but for the bearish among us, these are heartening signs.