(CNN) — Elon Musk sold $3.95 billion worth of Tesla stock since completing his purchase of Twitter late last month.

Musk’s Tesla stock sales, totaling 19.5 million shares, have been widely anticipated ever since the Tesla CEO reached a deal to buy Twitter for $44 billion. Musk had sold blocks of Tesla shares worth a total of $15.4 billion earlier this year since his deal to buy Twitter was announced.

Twitter confirmed Musk bought the social media company October 27, but he waited until November 4 to start selling additional Tesla shares. He also sold blocks of Tesla stock on Monday and Tuesday this week, according to filings to the Securities and Exchange Commission late Tuesday night.

It’s not clear if the money Musk raised went toward the Twitter purchase, or to support losses at Twitter since he took over.

Musk disclosed last week that Twitter has seen a “massive drop in revenue,” as a growing number of advertisers pause spending on the platform in the wake of his takeover of the company. He blamed “activist groups” pressuring advertisers for the loss of ad dollars.

He has announced plans to charge users $8 a month to have verified accounts, and also announced deep staff cuts.

Tesla’s falling stock

This is not the best time to be selling Tesla shares, which have lost 46% of their value so far this year on disappointing sales caused by supply chain problems. Musk received an average price of $202.52 for the Tesla shares he sold since the Twitter deal closed, which is down 10% just since he closed on his deal to buy Twitter.

Shares of Tesla fell 0.7% in after-hours trading Tuesday.

The company is facing growing competition in the electric vehicle market from established automakers such as Volkswagen, Ford and General Motors. And some investors have expressed concerns that Musk will be too distracted by his purchase of Twitter to give enough attention to addressing Tesla’s problems.

Musk’s stock sales

These three most recent blocks of Tesla stock sales represent only 4% of the shares that Musk owns outright through a trust, and less than 3% of his holdings if options that he has to buy additional shares are included.

Musk agreed to buy Twitter in April, shortly after filings showed he had purchased 73 million shares, or about a 9% stake, for $2.6 billion. The purchases made him the company’s largest shareholder.

Soon after the deal was announced, he disclosed he had sold $8.5 billion worth of Tesla shares, a move seen as a first step to raise the cash he would need to complete the purchase of Twitter.

Even after Musk announced a change of heart and fought a lawsuit brought by Twitter to force him to buy the company, he continued to sell Tesla shares. Filings in August showed he had sold an additional $6.9 billion worth of Tesla shares.

Musk’s filings did not disclose the reason for those earlier stock sales. But after someone on Twitter asked him if he was done selling Tesla shares, he responded “Yes” and then pointed to the possibility of being forced to buy Twitter as the reason for those sales.

Since Musk’s earlier Tesla sales, shares of Tesla have split three-for-one, meaning he needed to sell three times as many shares in order to raise as much cash. But his holdings of Tesla shares also tripled due to the split.

Before his interest in Twitter, Musk rarely sold shares of Tesla stock, primarily selling shares necessary to pay taxes when exercising stock options.

He sold a total of 15.7 million pre-split shares at the end of 2021, netting a total of $16.4 billion, because he had to exercise stock options or risk having them expire. He likely ended up with a tax bill of more than $10 billion. But even after paying that tax bill and the cost to exercise those options, he likely had roughly $5 billion left over. He may have used some of that cash to buy his initial Twitter stake.

— CNN Business’ Clare Duffy and Catherine Thorbecke contributed to this report