Tesla CEO Elon Musk has sold 19.5 million shares in the electric car maker worth $3.95 billion (£3.4 billion) in a filing with the US Financial Services Authority.
The news comes less than two weeks after the world’s richest man bought Twitter for $44 billion.
Tesla stock is down more than 50% since the beginning of the year.
Separately, Tesla has recalled over 40,000 vehicles in the US due to potential problems with power steering.
The reason for the latest sale, which took place last week, has not yet been revealed.
The sale brings nearly $20 billion in Tesla stock sold since Musk announced his purchase of Twitter earlier this year. He sold $8.5 billion worth of Tesla stock in April this year and another $7 billion in August.
He also said in August that Tesla shareholders approved his 3-for-1 stock split.
Electric car recalls
On Tuesday, Tesla recalled more than 40,000 cars in the US due to possible power steering problems.
The electric car maker said the car’s power steering assist system could fail after hitting a bumpy road or pothole.
The National Highway Traffic Safety Administration says it may require greater steering manoeuvres, especially at low speeds, which could increase the risk of accidents.
Tesla has released a software update to recalibrate the system.
There are no known injuries or fatalities related to the issue.