S&P 500’s War Pattern: The Wipeout Begins Every Thursday

Five weeks into a Middle East war that’s sending shockwaves through the global economy, the US stock market has settled into a predictable pattern. It starts the week on a strong note, drifts sideways toward the middle of the week and then, like clockwork every Thursday and Friday, collapses.

A similar dynamic, to one degree or another, has been playing out in European and emerging-market stocks and even some US Treasury bonds. It’s been particularly stark, though, in the S&P 500 Index. Since the Iran war began, it’s posted cumulative gains over the first three days of the week but cratered 9%, all told, on Thursdays and Fridays.