That’s because the correlation between crude oil and stocks has not been stable over time. For several decades prior to 2000, for example, that correlation was negative, as you can see in the chart below. During those decades, higher oil prices in a given month led to below-average stock-market returns in the subsequent month.

Wall Street strategists believe a big spike in oil prices could be the next major catalyst for equities if tensions continue to escalate in the Middle East.

Those moves extended as the day progressed, especially in the afternoon when Iran announced retaliatory measures. The strikes on a US air base in Qatar were viewed as a half-measu