In the days since the outset of the U.S.-Iran war, stock markets have followed a familiar historical pattern: an initial selloff on the news, followed by some volatility and a slight recovery.

“The U.S. equity selloff seems to have reversed in short order, which makes sense,” Scott Helfstein, head of investment strategy at investing firm Global X, wrote in a note earlier this week. “Geopolitical events generally lead to brief periods of heightened volatility, but markets are usually quick to recover losses and tend to move higher in the subsequent weeks.”

Indeed, since 1979, the S&P 500 has risen by 2.2%, on average, in the month following wars, geopolitical events and energy crises, according to data from Stock Trader’s Almanac.

During…