Apparently fed up with the agitation and indignities of running a public company, Elon Musk on Tuesday made some unorthodox news on his Twitter feed. Musk’s relentless social-media habit has already gotten him into trouble a half-dozen times this summer, such as when he went on a Trumpian rant against the media or accused a British cave diver of being a pedophile. On Tuesday, however, Musk’s unorthodox use may have constituted a crime. Or, at the very least, a violation of Securities and Exchange Commission best practices. “Am considering taking Tesla private at $420,” Musk tweeted, just hours after the Financial Times reported that Saudi Arabia’s sovereign wealth fund had bought a 3 to 5 percent stake in Tesla. “Funding secured.”

The FT report had already raised Tesla’s stock, but it soared on Musk’s tweet, with shares surging about 10 percent. Musk’s sworn nemeses, Tesla short-sellers, lost more than $800 million after Musk suggested taking his company private, according to estimates from financial-technology firm S3 Partners, while Musk reportedly gained $851 million on his tweet, which nobody besides Wall Street knew how to immediately react to. There is, after all, a procedure that public companies usually follow if they decide to go private. Typically, the company would halt trading or make an official statement, in order to comply with S.E.C. guidance and avoid sending shockwaves through the stock market. Musk simply tweeted the news. Tesla stock wasn’t frozen until about an hour and a half later, when the share price had already soared to nearly $370.

Securities experts aren’t so sure that Musk’s announcement—or his proposal to completely uproot Tesla’s corporate structure—is entirely kosher. Former S.E.C. Chair Harvey Pitt told CNBC that while S.E.C. guidelines made it clear in 2013 that executives could use social media to make statements about their companies, Musk’s tweet, which he called “highly unprecedented,” could be considered securities fraud if he was trying to manipulate the market: “[It] raises significant questions about what his intent was,” Pitt said. Securities lawyers, meanwhile, were shocked by the tweet. “I do not believe this is the appropriate way to suggest going private,” Charles Elson, the director of the John L. Weinberg Center for Corporate Governance at the University of Delaware, told CNBC.

These are extraordinarily high stakes for a Twitter update, even by the standards of Elon Musk. If the content of his tweet turns out to not be true, lawyers say, Musk and Tesla could face private lawsuits or regulatory action. “If he doesn’t have financing in place, but the deal happens anyway, then it may be, no harm, no foul,” Ira Matetsky, a partner at Ganfer Shore Leeds & Zauderer told Marketwatch. “If this was a pipe dream going nowhere, there will be a case.” (In a 2013 S.E.C. filing, Tesla said it disseminates company updates through a number of means, “including Tesla’s Web site, press releases, S.E.C. filings, blogs, and social media, in order to achieve broad, non-exclusionary distribution of information to the public.”)

Luckily for Musk, it appears he was tweeting in good faith. In the mid-afternoon, Tesla published a press release on its Web site called “Taking Tesla Private,” which confirmed Musk’s statement, but did not address the funding portion of his tweet. (The $420 per share number, contrary to CNBC’s speculation, was not a weed joke—instead, Musk said, it reflected a 20 percent premium over Tesla’s stock price after its second-quarter earnings.) Musk later elaborated, explaining Tesla shareholder options (“Shareholders could either to sell at 420 or hold shares & go private”), and confirming the backing of Tesla investors (“Investor support is confirmed. Only reason why this is not certain is that it’s contingent on a shareholder vote”).