After polling his Twitter followers whether he should sell 10% of his stock, Elon Musk sold $5 billion in Tesla shares this week.

According to filings with US securities authorities, Musk sold roughly half of the 2.1 million shares he got, collecting around $1.1 billion in cash to pay transaction taxes.

On Tuesday and Wednesday, he sold an additional 3.6 million shares. The sales totaled worth $3.8 billion with the average price of a share at $1,071.

Additional filings reported that Monday's sale was " "solely to satisfy [Musk's] tax withholding obligations related to the exercise of stock options."

Tesla shares rose 2.7% Wednesday.

The truth behind the Tweet

According to The New York Times, Elon Musk's pledge to sell 10% of his Tesla shares could be seen as a selfless philanthropic act if he hadn't been already forced to sell the amount.

He has roughly 23 million stock options, which were granted to him in 2012. Those options have subsequently been vested and their expiration date is August 2022. Most stock awards allow CEOs to avoid paying taxes for years, if not indefinitely if the shares obtained from converting the option are not sold.

Regardless of the poll, Musk may have been required to sell a significant portion of his stock in the near future. He has roughly 23 million stock options, which were granted to him in 2012. Those options have subsequently been vested and their expiration date is August 2022. Most stock awards allow CEOs to avoid paying taxes for years, if not indefinitely if the shares obtained from converting the option are not sold.