The SEC alleges Musk was able to underpay “by at least $150 million” for shares he bought after he should have disclosed his ownership of more than 5% of Twitter’s shares.

The SEC filed a lawsuit against Elon Musk, accusing him of failing to disclose his ownership of Twitter stock in a timely manner during early 2022.

Twitter's stock price rose 27 percent once Musk belatedly disclosed his stake, the lawsuit said. "During the period that Musk was required to publicly disclose his beneficial ownership but had failed to do so, he spent more than $500 million purchasing additional shares of Twitter common stock," it said.