A lot of investors are familiar with Stein’s law, named after the late economist Herbert Stein: “If something cannot go on forever, it will stop.”

Which brings us to Thursday’s gross-domestic-product report. The Commerce Department reported that the U.S. economy grew at an inflation-adjusted 4.9% annual rate, the biggest gain since the fourth quarter of 2021, and far stronger than the less-than-2% rate that Federal Reserve policy makers think it needs to settle in at to avoid overheating.