The company, valued at about $1.77 trillion at its IPO price of $135 per share, has been effectively inaccessible to most investors until it began trading on the Nasdaq just before midday on Friday.

Elon Musk is the world's first trillionaire.

SpaceX plans to sell 556 million shares at an initial price of $135 a share, the company confirmed Thursday, on track to be the biggest IPO in history.