The US Securities and Exchange Commission has filed a lawsuit against Tesla chief executive Elon Musk, in which it alleges securities fraud.
The suit stems from Mr Musk's claim last month that he had secured funding to take the publicly-traded firm private.
The regulator says Mr Musk had made no such plans.
The lawsuit was filed in the US District Court in Manhattan.
"In truth and in fact Musk had not even discussed much less confirmed key deal terms, including price, with any potential funding source," it says.