While they didn't support Musk's allegations directly, the feds added weight to his interpretation of antitrust law.

The U.S. Federal Trade Commission weighed in on Friday on Elon Musk's lawsuit seeking to block OpenAI's conversion to a public company, pointing out legal doctrines that could support his claim that OpenAI and Microsoft engaged in anticompetitive practices.

OpenAI launched a for-profit subsidiary a year later in order to raise outside capital, including more than $13 billion so far from its biggest backer, Microsoft. However, the non-profit entity, along with employees and investors, currently owns that for-profit subsidiary.

According to a report in the Financial Times, lawyers for Musk have contacted attorneys-general in Delaware and California to demand that a large stake in OpenAI be sold off in an open auction process.

His attorney argued they should provide a process for competitive bidding to determine fair market value of OpenAI's charitable assets to 'protect the public's beneficial interest,' as it is working on removing the control of its non-profit,

A lawyer for Elon Musk has called on the California and Delaware attorneys-general to force OpenAI to auction off a large stake in its business, intensifying a bitter fight with the company’s chief executive Sam Altman.