After its January release, DeepSeek’s AI app swiftly gained traction in the U.S., dominating the Apple and Google app stores and capturing Silicon Valley’s interest. By being significantly cheaper to develop, DeepSeek set itself apart from competitors like ChatGPT, Gemini, and Claude. It offered a unique “reasoning” AI chatbot that demonstrated the process behind its answers.

But employees of at least one major company aren’t allowed to use it.

At a Senate hearing on Thursday, Microsoft Vice Chairman and President Brad Smith expressed concerns about DeepSeek’s AI chatbot related to data security and the potential for “Chinese propaganda” within the app’s responses. As a result, Microsoft employees are strictly prohibited from using the DeepSeek app.

Smith explained, according to TechCrunch, “We don’t permit our employees to use the DeepSeek app” due to the primary concern of “data going back to China.”

Smith said that Microsoft has also blocked DeepSeek on its app store, the Microsoft Store. DeepSeek is not listed on the store at the time of writing.

This marks the first time a Microsoft executive has spoken publicly about a DeepSeek ban at the company. Microsoft joins other organizations, like NASA and the U.S. Navy, in blocking access to the app for staff.

^{Microsoft president and vice chairman Brad Smith. Photo by Chip Somodevilla/Getty Images}

One of Smith’s concerns was data privacy. DeepSeek’s privacy policy states that the company stores user data in China, where local laws require Chinese companies to share data with government officials upon request. This leads to concerns that the Chinese government could tap into user data for its own aims.

Still, it doesn’t mean Microsoft isn’t interested in Deepseek’s technology.

Since DeepSeek’s AI model is open source, anyone can download the model and store it on their own internal servers, without user data getting back to China. Microsoft offered the AI model behind DeepSeek through its Azure cloud service in January, days after the DeepSeek app went viral.

Smith mentioned during the Senate hearing that Microsoft downloaded the model and changed the code.

“It was possible for us to go in it, analyze it, and change the code in the model… to remove the harmful side effects,” Smith stated.

Smith was speaking before the Senate Committee on Commerce, Science, & Transportation at a hearing titled “Winning the AI Race: Strengthening U.S. Capabilities in Computing and Innovation.”

Microsoft is the most valuable company in the world at the time of writing, with a market cap of over $3.2 trillion.