The first trading day of September was awash in red, with the technology sector hard hit. Once high-flying Nvidia (NVDA) led the losses, although Apple, Microsoft, and Google were also down for the day.

Nvidia (NVDA) suffered the most during the Tuesday bloodbath, with its stock plunging 9.53% to $108 from its open at $116.02. The drop brought a massive contraction in the company’s total market cap.

The $270 billion fall from $2.92 trillion to $2.65 trillion was “the biggest one-day market cap decline on record for any U.S. company,” according to the Wall Street Journal.

The news got worse shortly after the markets closed, as Bloomberg reported that Nvidia was served with a subpoena from the U.S. Department of Justice as it investigates possible antitrust violations. NVDA is now trading even lower after hours, according to Google Finance.

In August, after Nvidia posted its second-quarter earnings report, the stock price fell 6% in after-hours trading to $125.61 per share.

Other top tech stocks also closed the day in the red.

Despite rumors of a future shift toward consumer robotics ahead of its next iPhone-focused event next week, Apple (AAPL) was also down Tuesday 2.72%, trading at $222.77. AAPL started the day trading at $229.00 before dropping to $221, although it has risen in after-hours trading. Apple currently has a market capitalization of $3.39 trillion, and it is currently the largest company by that metric.

Microsoft (MSFT) was down 1.85% for the day. Microsoft began the day trading at $415.40, and over the day, its stock price peaked at $419.80 before closing at $409.44. The company currently has a market cap of $3.04 trillion.

In August, Microsoft announced a deal with defense contractor Palantir to bring its AI technology to U.S. defense and intelligence agencies.

Google has invested heavily in artificial intelligence, adding the emerging technology to almost every facet of its consumer-facing offerings. Despite this intensified focus on generative AI, Google’s parent company, Alphabet (GOOGL), is down 3.68% on the day, falling from its opening price of $163.33 to close at $157.65. Its market cap stands at $1.95 trillion.