The S & P 500 was fighting in midday trading to break a streak of Thursdays being negative for the broad index. Over the last nine Thursdays, the index has ended in the red. It’s the longest streak going back to the 1980s. If the benchmark declines ends the session lower, the total of 10 in a row would be the longest negative streak ever for the weekday. Markets have traded in a fairly consistent pattern since the Iran war began: They rise to start the week on hopes that the war’s end — just to see those positive outlooks evaporate and the selling resume at the end of the week. “Early week optimism, and then the reality smacks us as we work our way later in the week that we’re not as close to the end of the conflict as we thought we were,” said Ryan Detrick, chief market strategist at Carson Group. On Thursday, markets initially declined after investors were left disappointed when President Donald Trump on Wednesday night failed to signal a clear path to end the war in Iran. At its session low, the S & P 500 fell 1.5%. Stocks, however, were able to erase much of their losses after a report that Iran and Oman are drafting a way to “monitor” traffic in the Strait of Hormuz. The weekly trading pattern is backed up by data. In a post on X , Bespoke Investment Group noted that the S & P 500 has averaged this year a 0.28% decline on Thursdays. Fridays are also negative on average, while Monday through Wednesday have on average been positive ones. “It’s certainly an incredible streak,” Bespoke co-founder Paul Hickey said in an email to CNBC, about the Thursday trend. He added that Fridays’ relative weakness too shows this trend is about investors not wanting to take on too much risk heading into the weekend, amid geopolitical uncertainty. “As long as the U.S. military has a massive and building presence in the Middle East, and Iran is saying ‘Bring it On,’ I would expect this pattern to continue in the short-term,” Hickey said.
