Twitchy Traders Have S&P 500 Comebacks Fizzling at Historic Pace

(Bloomberg) — Surprised that the S&P 500 swung into the green Friday? Don’t worry. Just wait. It’ll fall again after the next opening bell.

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That’s been the August trend, at least, thwarting any effort to revive the US stock-market rally since it stalled early this month.

Nineteen trading sessions have come and gone in August without a single back-to-back gain in the S&P 500. If that continues, it will be the first month without two consecutive up days since April…