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 sued Elon Musk, claiming he deliberately waited too long to disclose his purchase of more than 5% of Twitter shares in 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.