Did Elon Musk break U.S. securities laws again?

Former securities officials and professors said Tesla Inc.'s chief executive may have missed a key disclosure deadline and filed the wrong paperwork when he bought 9% of Twitter Inc., a platform regularly used by the outspoken billionaire. Securities and Exchange Commission regulators could use any shortfall to try to punish Musk more for other lapses, some believe.

Musk on Monday disclosed that he bought a 9.2% stake in Twitter, making him the microblogging site's largest shareholder and triggering a rise of more than 27% in the company's shares. The filing said that March 14 is the date of the event that required the disclosure.