Nvidia Shares fell 1% on Wednesday morning after Bloomberg reported that the company had received a subpoena from the Justice Department as part of an anti-monopoly investigation.

The drop comes after Nvidia fell nearly 10% in regular trading on Tuesday, wiping $279 billion from its market cap. The company’s shares subsequently fell in post-market trading.

According to Bloomberg, the DOJ’s investigation has not yet reached the stage of a formal complaint, and the agency is raising questions about whether Nvidia is making it harder to switch to other AI chip vendors. Industry estimates put Nvidia at more than 80% of the data center AI chip market.

Nvidia’s meteoric rise in recent years is directly tied to its dominance in data center AI chips, which it established years before rivals AMD and Intel began to take the category seriously. Nearly a decade ago, Nvidia developed a programming language for its chips called CUDA, which has become a critical tool for engineers training advanced AI models like the ones at the heart of ChatGPT.

Many of Nvidia’s largest customers are cloud companies and internet giants, including Microsoft, Alphabet, Meta, Amazon and Tesla.

As Nvidia’s AI chips have become a hot commodity, the company has released new enterprise software subscriptions and marketed its networking products as key additions to getting the most out of its chips.

Recent versions of Nvidia’s chips can be pre-installed in complete Nvidia-designed server racks. This is an example of Nvidia’s efforts to evolve from a component supplier to a complete systems supplier.

An Nvidia spokesperson told CNBC that the company “wins on the merits, as demonstrated by our benchmark results and the value to customers, who can choose the solution that best suits their needs.” The Justice Department declined to comment to CNBC.