The way I currently understand it, it will have a tendency to accelerate as it pushes past 5K towards 4980 because dealers will be forced to sell into the move to hedge their short put exposure.  That's assuming the street is net long 5K puts. Maybe they are net short puts because that's been a major trend recently? That would still cause an acceleration most likely because covering puts would lead to VIX spike.  Most likely outcome is a pin, but if it flips, it could get rough fast.