Billionaire bon vivant Elon Musk’s electric car empire has made him an international celebrity, but a lawsuit filed by the Securities and Exchange Commission on Thursday could take him out of the driver’s seat.

The SEC accused the CEO of Tesla Motors in federal court of fraud for a Aug. 7 tweet he sent claiming to have secured funding to take the company private. “In fact, Musk had not even discussed, much less confirmed, key deal terms, including price, with any potential funding source,” the SEC alleges.

That tweet, in which Musk announced he was “considering taking Tesla private at $420. Funding secured,” prompted a rush on Tesla stock that increased the company’s stock price by billions of dollars. Musk later admitted that while the funding was not secured, he was confident that an infusion of cash by Saudi Arabia’s sovereign wealth fund would provide the requisite capital to take Tesla private.

The SEC said that tweet and subsequent statements “left market participants with the false and misleading impression that if Musk chose to take Tesla private at $420 per share, the only outstanding requirement to be satisfied was a shareholder vote.” The suit also alleges that Musk arbitrarily set the price to take Tesla private at $420 per share “because he had recently learned about the number’s significance in marijuana culture and thought his girlfriend ‘would find it funny, which admittedly is not a great reason to pick a price.’”

In fact, the SEC alleged in its suit, Musk had never even discussed taking Tesla private, let alone with a Saudi wealth fund or any other investor.

The Wall Street Journal reports the SEC was prepared to file a settlement with Musk on Thursday, but Musk’s attorneys called and said they did not want to proceed with the agreement. The agency’s lawyers then reportedly “rushed” to compile the complaint that was filed to a federal court in Manhattan.

According to the newspaper, Musk and his lawyers made a “last-minute” decision to reject the settlement and fight the case.

The SEC now asks for civil penalties against Tesla and an order to prohibit Musk from acting as an officer or director of Tesla or any other publicly traded company.

In a statement Thursday evening, Tesla and its board of directors said they were “fully confident in [Musk], his integrity, and his leadership” of the auto company.

The charges sent shares of the automotive manufacturer into a nosedive, plummeting nearly 12 percent in extended trading.