Nvidia’s Jensen Huang is beginning to learn the meaning of the expression, “The higher they rise, the harder the fall.”

After briefly eclipsing Microsoft and Apple in value last week—and indeed entire European stock markets—the company behind the AI chip boom has experienced the single fastest drawdown in history.

Over the past three days, roughly $430 billion in Nvidia’s market cap has been wiped out, which is the biggest three-day value loss for any company in history. If you measure the drop from its intraday peak on Thursday, more than half-a-trillion dollars have gone up in smoke. That’s almost the entire value of Tesla knocked off its shares, which pose larger problems for the overall stock market.

“If Nvidia corrects pretty hard in the coming months, it becomes very difficult for the [S&P 500] to keep rising,” Barry Bannister, chief equity strategist at Stifel Financial, told the Financial Times.

It hasn’t helped either that the founder and CEO has inadvertently added to the pressure by cashing out himself. Huang’s Rule 10b5-1 trading plan, which automatically executes sales when certain conditions are met, liquidated 720,000 shares worth nearly $95 million this month alone.

The timing is unfortunate coming just before Wednesday’s annual shareholder meeting and two weeks after a 10-for-1 stock split that made it easier for retail investors to buy into the company. One indication many amateur traders might be taking profits in Nvidia is a sudden slump in Bitcoin, an asset highly correlated to the retail market since it is largely untouched by institutional investors.

Harvest Portfolio Management co-CIO Paul Meeks blamed the drop on profit taking and talk of AI data center spending peaking.