If history is any guide, one stock market gauge suggests that Vice President Kamala Harris will defeat former President Donald Trump in the 2024 presidential race. 

In all but two elections since 1944, the party in the White House has retained power when the U.S. stock market advances before Election Day, or the period between the end of July and Halloween, according to an election predictor devised by Sam Stovall, chief investment strategist at CFRA Research, based out of Allentown, Pennsylvania. 

In 2020, the S&P 500 fell 0.04% from July 31 to October 31, with then-President Donald Trump losing the election to President Joe Biden. While the outcome in the 2024 election is not yet known, the S&P 500 rose 3.3% during that three-month span this year.

To be sure, many other factors can influence a presidential race, and Wall Street is no stranger to making wrong predictions, ranging from the direction of the stock market to election outcomes. And betting markets that allow average investors to place wagers on the election outcome have in recent weeks favored Trump.

“You can say there is sort of an overlap — the market usually goes up on an annual basis and voters tend to give the incumbent the benefit of the doubt, so it makes sense if the market goes up most of the time and the incumbent gets re-elected most of the time,” Stovall told CBS MoneyWatch.

Even more reliable are periods when the stock market falls during the period from July 31 to October 31, in which case the incumbent has been replaced 89% of the time. That predictor failed only once, in 1956, according to Stovall, pointing to the year when incumbent President Dwight Eisenhower defeated Adlai Stevenson, despite the S&P 500 tumbling 7.7% in the period ahead of the election.

Still, Stovall notes a mathematician might scoff at basing a model on such a limited sample, in this case the 21 presidential elections held in the U.S. since World War II. 

“Is this really statistically significant? I think the answer is no, but it makes for interesting copy,” the strategist said. “You can have data tell whatever story you want.”

Limited or not, Stovall is sticking with his presidential predictor.  

“I believe we will see a Harris victory ultimately, because I’m a very big believer in history and rules-based investing,” Stovall told CBS News.