The world's richest man, Elon Musk, on Monday sold shares in his electric vehicle manufacturer, Tesla, with which he raised about $1.1 billion.

Tesla's CEO sold about 930,000 shares, according to the Securities and Exchange Commission (SEC), the US market regulator.

The stock sale came after over the weekend Musk polled the opinion of his Twitter followers when he announced that he intended to sell 10% of the 17% shares he owns in Tesla, which could earn him more than $20 billion.

The amount raised from the stock sale on Monday is to pay income tax on stock options that he also exercised that day.

Over the subsequent two days, Musk continued with the stock sale, and according to the SEC, Musk has so far sold more than 4.5 million shares.

Meanwhile, Musk's probe led to a 16% drop in Tesla shares in two days, as investors worried about the consequences of getting rid of a sizable block of shares.

The documents do not clarify whether the Tesla CEO's research will have influenced for the decision to do some or all of the transactions, or whether Musk will continue with the stock sale until he reaches 10%, but to do so he would need to sell 17 million shares.

Nevertheless, it is possible that the option exercises and related sales were executed regardless of the outcome of the Twitter survey, since they were done under a pre-established plan.  

Still, the Twitter referendum hit Tesla shares on Monday and Tuesday, wiping $50 billion off Musk's net worth. Tesla rose 4.3% on Wednesday to close at $1,067.95, cutting losses this week to less than 13%.

After the first trades were released, the stock was up 2.7% in the after-market.