Elon Musk’s SpaceX on Thursday confirmed it will begin trading on the Nasdaq exchange Friday in the biggest initial public offering in history, a blockbuster market debut that could propel the entrepreneur to trillionaire status.In a filing with the US markets regulator, the company priced more than 555 million shares at US$135 each, placing SpaceX in the top 10 of Wall Street’s biggest companies with a valuation of just under US$1.8 trillion.It will be valued more than Musk’s own Tesla car...