The unpredictable billionaire posted the poll shortly after apparently acknowledging he had made a mistake banning Twitter users from promoting their accounts on rival social media platforms. "Going forward, there will be a vote for major policy changes. My apologies. Won't happen again," he tweeted.

Musk's selloff came days after he created a Twitter poll in which millions voted asking whether he should sell 10 percent of his huge stake in the electric carmaker.

Musk owned about 17 percent of Tesla's outstanding shares as of June 30, currently worth $208.37 billion. His wealth swelled with the recent surge in Tesla's stock price. By selling 10 percent of his shares, he could theoretically earn just under $21 billion. His wealth swelled with the recent surge...