Shares in SpaceX jumped on their debut on Friday, catapulting the business to becoming one of the most valuable firms in the world and making Elon Musk the world’s first trillionaire.The group’s shares opened at $150, compared to the listing price on Thursday evening of $135. Shares in the group, which counts the Starlink internet service and xAI as well as the space transportation business among its units, increased further in their first minutes of trading to a high of $168.75, valuing the business at $2.2 trillion.SpaceX is making its historic debut at a pivotal moment for Wall Street, with shares in highly valued companies that have soared over the past year swinging sharply in recent days amid concerns the market is overheating.The share price pop has confirmed Musk as the world’s first trillionaire. His 42 per cent stake in the rocket group is worth about $924 billion (€798 billion) which, when combined with his $280 billion holding in electric-vehicle maker Tesla, pushes his wealth comfortably beyond $1 trillion.Speaking from Starbase, Texas, ahead of the market open, Musk said it was “hard to believe that a little company . . . is now going public [in] the largest IPO ever”.“If people had told me this was going to happen, I was like, man, you must be smoking some really good crack, because I think this company is going to fail,” he added.SpaceX on Thursday sold more than 555 million shares at $135 each in the world’s biggest initial public offer. The total fundraising could rise to $86 billion if underwriters exercise a so-called greenshoe option to sell additional shares.SpaceX drew orders for more than three times the amount on offer in its IPO as huge asset managers, Gulf sovereign wealth funds, hedge funds and retail investors clamoured for shares, according to people familiar with the matter.Individual investors placed orders for more than $100 billion, and will be allocated 20 to 25 per cent of the SpaceX shares sold. Bank of America ran the US retail part of the deal.The company’s performance on the Nasdaq in the coming days will provide a crucial test of investors’ appetite for massive listings, as Claude maker, Anthropic and ChatGPT developer, OpenAI are plotting their own IPOs.“The volatility is always highest fresh out of the gate because you ​have all that pent up demand and investors just trying to figure it out,” said Don Calcagni, chief investment officer at Mercer Advisors said. “That’s why people get excited, they see this huge pop and want ‌a piece of it. “If they buy it today, ​they might not be getting that huge pop themselves, but they are funding the exponential returns of all the early investors.” - Additional reporting: Reuters/Bloomberg