According to US regulatory filings, Musk has sold almost $4 billion worth of shares in the electric car maker.
Mr Musk has no plans to sell more shares in the company.
Concerns that he will sell part of his stake in the firm to help pay for his takeover of the social networking site caused the shares of the company to plunge.
The board of the social media platform unanimously accepted a $44 billion offer from the world's richest person on Monday.
On Tuesday and Wednesday, Mr Musk sold a total of over four million shares in the company.
The sale has led to speculation that it was going to help finance Mr Musk's planned acquisition of Twitter.
No further TSLA sales are planned after today. The stock quote of TSLA is listed on the New York Stock Exchange.
In after-hours trade, the shares were 2.5% lower.
It was his first sale of stock in the company since November and December of last year.
He asked his more than 80m followers if he should sell 10% of his stake in the electric car maker.
Mr Musk revealed earlier this month that he had bought a 9.2% stake in the micro-messaging service.
On Tuesday alone, more than $125 billion was wiped off the car maker's stock market value after the social media firm's board accepted his takeover offer.
Mr Musk said he would give $21 billion of his assets to finance the deal.
He may have to sell shares to help fund the takeover.
The richest person in the world is Mr Musk, with an estimated net worth of $250 billion.
He has a 40% stake in the rocket company, which is worth $100 billion.