Tesla boss Elon Musk has sold 19.5 million Tesla shares worth almost $4 billion since he took over Twitter, according to regulatory filings.

He'd already sold about $20 billion since his stake in Twitter became known in April, and the automaker's stock is down 52 percent for the year.

Musk finalized the deal to buy Twitter on October 27, and he sold the shares between November 4 and 8.

It's difficult, if not impossible, to tell, at least this early, if Musk's ownership of Twitter is negatively impacting Tesla. In fact, it may be his ownership of Tesla that is hurting Twitter, as automotive brands pull out of advertising on the platform, perhaps because they don't want to advertise on a social-media site owned by a competitor.

Tesla, of course, has its own problems. Quality issues have plagued the company for years, Cybertruck production is continually delayed, the company's products are still mostly accessible only to luxury shoppers, and on and on.

That's not to say we're bringing back a Tesla Death Watch or anything -- only that Musk and his Tesla employees have their hands full.

[Image: Sergei Elagin/Shutterstock.com]

Become a TTAC insider. Get the latest news, features, TTAC takes, and everything else that gets to the truth about cars first by  subscribing to our newsletter.