Stock markets crashed globally yesterday and this morning, even though Nvidia, the world’s most valuable company, delivered blowout, above-expectations earnings. The company’s shares declined 3.15% yesterday. And the bloodletting continued for the red-hot semiconductor maker today: Nvidia was down another 3% by midmorning’s trading.

Still, the S&P 500 as a whole was flat by lunchtime, seemingly holding its own despite the storm in tech stocks. The Dow Jones Industrial Average was up.

Why?

It’s not just about a lot of negative headlines about AI.

The context here is that Nvidia stock is up more than 31% year to date—nearly three times the gain of the S&P as a whole. So a lot of this selling looks like people who are quite rationally deciding to cash in some of those gains while they can.