Tesla CEO Elon Musk sold a total of $6.9 billion in shares in the electric car company last week, capitalizing on a spectacular surge that increased the company’s valuation to more than $1 trillion.

According to a U.S. securities filing issued later that day, the billionaire sold 1.2 million shares held by his trust for more than $1.2 billion on Friday, the latest in a flurry of his stock transactions.

Last Saturday, the world’s richest individual and Tesla’s largest shareholder tweeted that he would sell 10% of his shares if followers of the social media site approved of the move. At the time of his tweet, he had approximately 17 million shares.

He has sold 6.36 million shares this week – around 37% of 17 million. He now needs to offload about 10 million more shares to fulfill his pledge to sell 10% of his holdings.

Shares of Tesla Inc closed lower on Friday, down 2.8% at $1,033.42, snapping an 11-week winning streak. The shares are up more than 46% this year following a sharp rally in October.

The stock sales, which marked the first time that Musk cashed out on a stake of that size since the company was founded in 2003, were massive by capital market standards, eclipsing the initial public offerings of most companies.

By getting Twitter users to green-light the move, he has blunted potential criticism of cashing out at a time when Tesla’s valuation has become frothy and shares are at record highs.

STILL MOST VALUABLE U.S. AUTOMAKER

Tesla shares fell 15.4% this week and lost some $187 billion in market value, more than the combined market capitalizations of Ford Motor Co and General Motors Co.

Despite the week’s losses, Tesla remains the world’s most valuable automaker. The stock’s recent robust increases have highlighted the desire for shares of electric vehicle (EV) manufacturers.

Following Rivian Automotive Inc’s market launch on Wednesday, the two most valuable automakers in the United States are EV firms.

Musk tweeted on Thursday, “There have been hundreds of automotive startups, both electric & combustion, but Tesla is (the) first American company to attain high volume production & positive cash flow in the previous 100 years.”

MORE SALES?

Musk had previously said he would have to exercise a large number of stock options this year, which would create a big tax bill. Selling some of his stock could free up funds to pay the taxes.

Prior to the sale, Musk owned a stake of about 23% in Tesla, including stock options. After his exercise on 2.15 million stocks on Monday, he has options for 20 million more shares he needs to exercise by next August.

“We expect the share sales will continue, as Musk holds millions of options worth billions of dollars that would otherwise expire worthless, and he has also prearranged share sales under 10b5-1 plans,” said Jason Benowitz, senior portfolio manager at the Roosevelt Investment Group LLC in New York.