Despite experiencing some turbulence earlier this year, the stock market has been on fire throughout 2025. The S&P 500 is up by close to 15% year to date as of this writing on Oct. 20, and it’s surged by more than 35% since its low point in April this year.
While it’s hard to see a downside in stock market gains, what goes up must come down eventually. Some experts have suggested that we’re in a bubble, fueled primarily by the artificial intelligence (AI) boom, and that we could be on the verge of a significant downturn.
To be clear, nobody knows exactly what the future holds for the stock market. But according to one stock market indicator, investors could be “playing with fire” right now.
This post originally appeared at The Motley Fool.