Are we in a stock market bubble?

NYTimes:

Preview of 7th edition: As of late 2025, the U.S. stock market’s cyclically adjusted price-to-earnings (CAPE) ratio has climbed above 40—its highest level since 2000. The CAPE compares stock prices to a decade of inflation-adjusted earnings. In principle, valuations should mirror the present value of expected future profits. High CAPEs can be justified if productivity and earnings growth from artificial intelligence and other innovations materialize—but if those expectations falter, prices tend to revert toward long-run earnings. As of October 2025, the CAPE stands near 39.5, more than double its historical average of 17.