The US markets watchdog has filed a lawsuit against Elon Musk alleging he failed to disclose that he had amassed a stake in Twitter, allowing him to buy shares at "artificially low prices."
The Securities and Exchange Commission (SEC) lawsuit alleges that the multi-billionaire Tesla boss saved $150m (£123m) in share purchases as a result.
According to SEC rules, investors whose holdings surpass 5% have 10 days to report that they have crossed that threshold. Musk did so 21 days after the purchase, the filing says.
In a social media post, Musk called the SEC a "totally broken organisation."