Will the next >=10% single day change in the S&P 500 be an increase?
8
23
240
2029
29%
chance

increase = YES

decrease = NO

How we define a "single day change":

If it ended on say, Tuesday at 1000. And then at end of day Wednesday it is 1050 or higher, that is a >=5% change. Changes within a single day which aren't the closing price are irrelevant.

We take (end of prior day) => (end of day in question) as the change, so that we treat "overnight changes" as being part of the subsequent day.

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