Elon Musk sold $4 billion of Tesla shares over 2 days but says he's now done selling, as he closes his Twitter buyout deal

• Elon Musk sold 4.4 million Tesla shares worth $4 billion over two days this week, SEC filings show.
• The billionaire is raising funds to complete his $44 billion deal to acquire Twitter.

Tesla founder and CEO Elon Musk sold $4 billion worth of Tesla shares over two days, five SEC filings on Thursday show.

The sale of 4.4 million shares took place on April 26 and 27, just days after Twitter agreed to the billionaire's $44 billion offer to take the company private.

"No further Tesla sales planned after today," Musk tweeted after the filings were made public.

The sale comes as Musk raises funds to complete his Twitter acquisition.

Musk needed to use his Tesla stock to raise $21 billion in equity to fund his $44 billion takeover of Twitter, Insider's Aaron Weinman reported previously. Some $13 billion will be from debt, while another $12.5 billion will come through a margin loan with his Tesla shares as collateral, per the report.

Musk's latest purchase is unnerving Tesla's shareholders, some of whom are retail investors. They're concerned that Twitter's inability to generate income will in turn force the billionaire to turn elsewhere to raise more money to pay the debt needed to finance the privatization deal, Insider's Linette Lopez wrote.

Tesla's market value has been shrinking ever since April 4, when Musk disclosed a 9.2% stake in the social media platform. On April 26, the day Musk struck a deal to buy Twitter, the electric carmaker's share price fell 12%, per Lopez's report.

Tesla's shares closed at $877.51 apiece on Thursday before the filings about Musk's offloading of his stake were made public.