Elon Musk has sold nearly $9 billion worth of Tesla stock in 2 weeks — but he's only halfway toward selling 10% of his stake

• Elon Musk has sold close to $9 billion of Tesla stock in the past two weeks.
• The Tesla CEO is only halfway towards satisfying his Twitter pledge to sell 10% of his stake.

Elon Musk has cashed in nearly $9 billion worth of Tesla stock in the past two weeks, but he's still only halfway toward fulfilling his pledge to sell 10% of his stock.

The Tesla CEO sold 8.2 million shares in total, generating $8.8 billion in proceeds, Securities and Exchange Commission filings show. The sales have precipitated a 7% drop in the automaker's stock price, erasing roughly $84 billion from its market capitalization.

Despite its recent slump, Tesla stock is still up 56% this year, and has skyrocketed by more than 1,300% since the start of last year. Musk still owns 164 million shares, giving him a 17% stake in the electric-vehicle company.

There are several theories around why Musk is on a selling spree. For example, the Tesla chief noted last year that he would need to sell shares to cover the cost of exercising stock options that expire next year.

Musk has also come under fire for paying virtually no income tax, and has clashed with lawmakers pushing for a "billionaire tax" that would hit the ultra-wealthy's unrealized gains. He cited that conflict when he launched a Twitter poll two weekends ago to ask whether he should sell 10% of his Tesla stake. However, it soon emerged that Musk had already established a trading plan to sell stock, calling the point of the whole spectacle into question.

Meanwhile, Michael Burry of "The Big Short" fame highlighted that Musk had taken out personal loans against 88 million of his shares at the end of June, and asserted that the Tesla chief might be raising cash to service his debts.

In another tweet, Burry noted that Musk described Tesla's stock price as "too high" in May 2020, and suggested Musk might simply be selling because he knows the company is massively overvalued.

Musk was apparently irked by the comment, or perhaps Burry's repeated warnings that Tesla stock is a bubble about to burst, as he dismissed the investor as a "broken clock" on Twitter.

The Tesla chief needs to sell close to 9 million more shares to satisfy his 10% commitment. At the current rate of selling, his disposals are set to continue for a couple more weeks at least.