Nvidia is under scrutiny from the U.S. Department of Justice (DOJ), which has issued subpoenas as part of an antitrust investigation into the company's dominant position in the AI chip market and potential anti-competitive practices. The investigation is examining whether Nvidia is penalizing customers who do not exclusively use its chips and whether it gave preferential treatment to those who do. This has resulted in a significant market reaction, with Nvidia's stock experiencing a record $279 billion drop in market capitalization. Nvidia has denied receiving a subpoena and stated that it wins on merit and value to customers. The probe also includes Nvidia's acquisition of RunAI and its impact on the market. The DOJ's investigation could have broader implications for other AI stocks and the tech industry at large.