US antitrust enforcers are opening an investigation into the relationships between leading artificial intelligence startups such as ChatGPT-maker OpenAI and Anthropic and the tech giants that have invested billions of dollars into them.

“We’re scrutinizing whether these ties enable dominant firms to exert undue influence or gain privileged access in ways that could undermine fair competition,” said Lina Khan, chair of the U.S. Federal Trade Commission, in opening remarks at a Thursday AI forum.

The FTC said it has issued “compulsory orders” to five companies requiring them to provide information regarding investments and partnerships. All of the leading cloud providers — Amazon, Google and Microsoft — have made huge investments into AI firms, most notably Microsoft's close partnership with OpenAI.

Both Google and Amazon have made multibillion-dollar deals with Anthropic, another San Francisco-based AI startup formed by former leaders at OpenAI.

The European Union and the United Kingdom have already signaled that they might also scrutinize the relationship with Microsoft and OpenAI. The EU's executive branch said in January it was checking whether the partnership might trigger an investigation under regulations covering mergers and acquisitions that would harm competition in the 27-nation bloc.

The review could lead to a formal investigation into whether the deal should be unconditionally cleared, allowed with concessions from the companies or blocked. Britain’s antitrust watchdog opened a similar review in December.

Microsoft has never publicly disclosed the total dollar amount of its investment in OpenAI, which CEO Satya Nadella has described as a “complicated thing.”

“We have a significant investment,” he said on a November podcast hosted by tech journalist Kara Swisher. “It sort of comes in the form of not just dollars, but it comes in the form of compute and what have you.”

Microsoft made its first $1 billion investment in San Francisco-based OpenAI in 2019, more than two years before the startup introduced ChatGPT and sparked worldwide fascination with AI advancements.

As part of the deal, the Redmond, Washington software giant would supply computing power — such as from one of its data centers in rural Iowa — needed to train the AI models on huge troves of human-written texts and other media. In turn, Microsoft would get exclusive to rights to much of what OpenAI built, enabling the technology to be infused into a variety of Microsoft products.

Nadella in January compared it to a number of longstanding Microsoft commercial partnerships, such as with chipmaker Intel. Microsoft and OpenAI "are two different companies, answerable to two sets of different stakeholders with different interests,” he told a Bloomberg reporter at the World Economic Forum in Davos, Switzerland.