(Reuters) – Tesla Inc (TSLA.O) Chief Executive Officer Elon Musk sold $8.5 billion in shares in the electric vehicle company, according to U.S. regulatory filings, presumably to help fund his planned acquisition of Twitter Inc. (TWTR.N).

Musk announced in a tweet on Thursday that “no additional TSLA sales are planned after today.” According to the papers on Thursday and Friday, he sold around 9.6 million shares this week, amounting to 5.6 percent of his interest in the firm.

It was unclear whether all of Musk’s recent Tesla share sales had been declared. Tesla did not immediately reply to a Reuters request for comment.

The sale comes after Musk said on Monday that he had agreed to acquire Twitter for $44 billion in cash, transferring ownership of the social media network populated by millions of users and global leaders to the world’s richest person. According to Forbes, Musk’s net worth is $268 billion.

Musk stated that he will contribute a $21 billion equity investment as part of the agreement.

It was unclear how the billionaire planned to finance the remaining $12.5 billion in stock funding. Musk owns 43.61 percent of the unlisted rocket business SpaceX, which is said to be worth $100 billion.

Tesla shares were up roughly 5% in morning trade on Friday.

Since Musk’s April 4 admission of a more than 9% interest in Twitter, they had fallen around 20%.

According to Reuters, Musk has been seeking for partners to lower his equity stake to the purchase, but it is far from likely that such a partner would materialise.

This is his first Tesla stock transaction since selling $16.4 billion in shares in November and December after polling Twitter followers about selling 10% of his ownership in the electric carmaker.

Musk stated on Twitter that he will pay more than $11 billion in taxes in 2021 as a result of exercising stock options that are supposed to expire this year.

Musk got pledges for $13 billion in loans secured against Twitter and a $12.5 billion margin loan related to his Tesla equity as part of the Twitter financing arrangement.