Tesla Inc's (TSLA.O) CEO Elon Musk sold $687 million worth of shares in the electric vehicle company on Thursday, adding to the $5 billion in stock sales earlier this week, regulatory filings showed on Friday.

According to the filing, Musk sold 639,737 shares in multiple transactions worth between $1,056.03 to $1,104.15 a share. 

As of 2:53 p.m., Tesla shares were trading at $1,023.20, down 3.79%, or $40.31.

Before the initial sale, Musk asked his almost 65 million Twitter followers whether he should sell 10% of his Tesla stock. Of those who responded, 58% supported the decision. Though Musk followed the results, he likely would need to sell around 12 million additional shares or more to stick to his Twitter pledge, the Wall Street Journal noted.

Meanwhile, CNBC reported that some of the shares were also sold in part to satisfy tax obligations related to an exercise of stock options. 

Musk, who stands as the world’s richest man, still owns more than 167 million shares of Tesla. 

The stock sales marked the first time that Musk cashed out on a stake of that size since the company was founded in 2003, Reuters noted.

Though Tesla stocks declined by roughly 13% through Thursday, the automaker is still the most valuable U.S. automaker, with the company valued at more than $1 trillion and shares still trading near record highs.