Tesla CEO Elon Musk has purchased $1 billion worth of Tesla shares. Chip Somodevilla/AFP/Getty Images

Elon Musk bought $1 billion worth of Tesla shares on Friday, according to a regulatory filing he made early Monday.

The purchase represents a rare action – by Musk or any other CEO. Few business leaders using their own money to buy their company’s stock without exercising of options.

Tesla investors viewed Musk’s stock purchase as a vote of confidence in the company and a further commitment by Musk to stay at Tesla. The news lifted shares of Tesla ( TSLA ) 7% premarket.

This is a developing story. It will be updated.

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