(Reuters) – U.S. securities regulators on Thursday accused Tesla Inc. CEO Elon Musk of fraud and sought to ban him as an officer of a public company, saying he made a series of “false and misleading” tweets about potentially taking the electric car company private last month.

Mr. Musk is one of the highest-profile tech executives to be accused of fraud by the Securities and Exchange Commission. Losing its public face and guiding force would be a big blow for money-losing Tesla, which has a market value of more than $50 billion, chiefly because of investors’ belief in Mr. Musk’s leadership.

Tesla shares tumbled 12% in after-hours trading. Tesla was not immediately available for comment.

The SEC’s lawsuit, filed in Manhattan federal court, comes less than two months after Mr. Musk told his more than 22 million Twitter followers on Aug. 7 that he might take Tesla private at $420 per share, and that there was “funding secured.”

“Neither celebrity status nor reputation as a technological innovator provides an exemption from federal securities laws,” Stephanie Avakian, co-director of enforcement at the SEC, told a news conference announcing its charges against Mr. Musk.

Mr. Musk has long used Twitter to criticize short-sellers betting against his company, and already faced several investor lawsuits over the Aug. 7 tweets, which caused Tesla’s share price to gyrate.

According to the SEC, Mr. Musk “knew or was reckless in not knowing” that his tweets about taking Tesla private at $420 a share were false and misleading, given that he had never discussed such a transaction with any funding source.

The SEC said he also knew he had not satisfied other contingencies when he declared unequivocally that only a shareholder vote would be needed.

Thursday’s complaint also seeks to impose a civil fine and other remedies. The SEC does not have criminal enforcement power.

On Aug. 24, after news of the SEC probe had become known, Mr. Musk blogged that Tesla would remain public, citing investor resistance.