Nov 15 (Reuters) - Billionaire entrepreneur Elon Musk

expanded his lawsuit against ChatGPT maker OpenAI, adding

federal antitrust and other claims and adding OpenAI's largest

financial backer Microsoft ( MSFT ) as a defendant.

Musk's amended lawsuit, filed on Thursday night in federal

court in Oakland, California, said Microsoft ( MSFT ) and OpenAI

illegally sought to monopolize the market for generative

artificial intelligence and sideline competitors.

Like Musk's original August complaint, it accused OpenAI and

its chief executive, Samuel Altman, of violating contract

provisions by putting profits ahead of the public good in the

push to advance AI.

"Never before has a corporation gone from tax-exempt charity

to a $157 billion for-profit, market-paralyzing gorgon - and in

just eight years," the complaint said. It seeks to void OpenAI's

license with Microsoft ( MSFT ) and force them to divest "ill-gotten"

gains.

OpenAI in a statement said the latest lawsuit "is even more

baseless and overreaching than the previous ones."

Microsoft ( MSFT ) and lawyers for Musk did not immediately respond

to requests for comment.

Musk has a long-simmering opposition to OpenAI, a startup he

co-founded and that has since become the face of generative AI

through billions of dollars in funding from Microsoft ( MSFT ).

Musk has gained new prominence as a key force in U.S.

President-elect Donald Trump's incoming administration. Trump

named Musk to a new role designed to cut government waste, after

he donated millions of dollars to Trump's Republican campaign.

The expanded lawsuit said OpenAI and Microsoft ( MSFT ) violated

antitrust law by conditioning investment opportunities on

agreements not to deal with the companies' rivals. It said the

companies' exclusive licensing agreement amounted to a merger

lacking regulatory approvals.

In a court filing last month, OpenAI accused Musk of

pursuing the lawsuit as part of an "increasingly blusterous

campaign to harass OpenAI for his own competitive advantage."