Maria Aspen

Tonight, we sent a message.

Wall Street has been hitting record highs, despite worsening economic data, ongoing uncertainty about tariffs, and the federal government shutdown.

But big companies are reporting big profits, and investors are particularly optimistic about the tech giants powering the AI boom.

These companies dominate the Nasdaq and the broader S&P 500 index, meaning that if tech stocks are having a great run, so is the overall market.

But the opposite also holds true.

And some investors are increasingly worried about what happens if the tech bubble pops.

On Tuesday, the CEOs of Goldman Sachs and Morgan Stanley both urged investors to be ready for an eventual market sell-off.

Hours later, the Nasdaq closed down more than 2%.

Maria Aspin, NPR News, New York.