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.

U.S. crude oil futures rallied more than 6 percent to peak at $78 a barrel, more than $1 higher than the price on Jan. 20 when Trump was inaugurated. That jump is likely to filter through to gasoline prices just as drivers prepare to hit the road for the long July 4 weekend next week.