NEW YORK (AP): SpaceX says it plans to raise up to US$75 billion when it goes public this month, setting the stage for the largest-ever stock market debut and putting Elon Musk on course to becoming the world's first trillionaire.

The company, formally known as Space Exploration Technologies Corp, said on Wednesday it will sell 555.6 million shares at US$135 apiece. The offering would give SpaceX a market value of US$1.77 trillion. Only six companies in the S&P 500 are currently worth more, with Nvidia tops at US$5.2 trillion.

Besides the size of the offering and the expected proceeds, SpaceX's amended prospectus updates details about how much control of the company Musk will have. As SpaceX's CEO, chief technical officer and chairman, Musk's voting power will come primarily through his ownership of 5.22 billion Class B shares, which give the holder 10 votes for every share held. According to the filing, Musk would have 82.4 per cent of the voting power in the company.