The market moved in reaction to the totality of events that happened in the world all averaged out through the actions of the participants, anyone who says "this" was what happened on any day is wrong. Some days have dominating factors but even if the event is the dominant one, the reason why it has the impact it does might be a 3rd or 4th level effect.
Thank you! So sick of people always ascribing the market's movement to whichever narrative headline they pick that day.
> anyone who says "this" was what happened on any day is wrong
There is never a singular reason. But there are negligible reasons. S&P not changing its rules was a negligible reason for today's tanking.