Elon Musk's costly tweets that sparked SEC fury and tanked Tesla stock

From declaring "funding secured" for a Tesla buyout to taunting regulators and wiping billions off his company's value, Elon Musk's prolific and often chaotic use of Twitter (now X), has resulted in a long history of high-stakes legal battles and financial turmoil.

The Tesla CEO's most infamous social media moment came in August 2018, when he posted he was considering taking the electric car company private at $420 a share, adding, "Funding secured."

This single tweet sent the stock price surging and triggered an immediate investigation by the US Securities and Exchange Commission (SEC), as reported by The Guardian.

The SEC concluded the tweet had "no basis in fact" and charged Musk with securities fraud. The resulting settlement cost Musk and Tesla $20 million each in fines, forced Musk to step down as Tesla's chairman for three years, and required him to have his market-moving tweets pre-approved by legal counsel.

Days after settling, a defiant Musk mocked the agency on Twitter, rebranding it the "Shortseller Enrichment Commission" and sarcastically praising its "incredible work."

He continued to flout the settlement's terms. On 1 May 2020, Musk tweeted, "Tesla stock price too high imo." The market reaction was swift and brutal. According to the BBC, the post wiped $14 billion off the carmaker's value and knocked $3 billion off Musk's own stake.

One analyst described the unpredictable posts as a "headache for investors," telling Reuters that "his tweeting remains a hot button issue and [Wall] Street clearly is frustrated."

Musk's online feuds have also landed him in court for defamation. In 2019, he faced trial after baselessly calling British cave diver Vernon Unsworth a "pedo guy" in a tweet to his 22 million followers. The comment came after Unsworth criticised Musk's offer of a mini-submarine to help rescue a youth football team trapped in a Thai cave.

"It was wrong and insulting, and so I insulted him back," Musk testified in court, claiming he was upset by what he called "an unprovoked attack." He was ultimately exonerated by the jury.

More recently, his chaotic $44 billion acquisition of Twitter in 2022 became the subject of a class-action lawsuit from shareholders. They argued Musk deliberately tried to drive down Twitter's stock price with his public statements to either renegotiate the deal or abandon it entirely.

In March 2026, a San Francisco jury found Musk liable for misleading investors, though it cleared him of a more serious charge of scheming to defraud.

"I think the jury's verdict sends a strong message that just because you're a rich and powerful person, you still have to obey the law," said Joseph Cotchett, an attorney for the plaintiffs.

The legal battles with regulators continued into 2026. In May, a trust in Musk's name agreed to pay a $1.5 million fine to settle an SEC lawsuit accusing him of waiting too long to disclose his initial stake in Twitter.

The agency had argued the 11-day delay allowed him to buy shares at artificially low prices, saving him an estimated $150 million, though the settlement did not require him to repay that sum.

Amanda Fischer, a former SEC chief of staff's aide, called it an "embarrassing day for the SEC," saying the settlement "should cause the public to question whether the SEC is protecting White House insiders at the expense of ordinary investors.”