SpaceX raised $10bn (£7.5bn) more than initially thought when it sold shares to the public on Friday - bringing in a total of $85.7bn.

Elon Musk's rocket company pulled off the biggest initial public offering (IPO) in history when it joined New York's Nasdaq stock exchange last week.

The listing had raised $75bn from investors, which Musk told employees will be spent funding a "significant growth phase".

But the banks which backed the IPO exercised a so-called "greenshoe" clause, which let them purchase an extra $10bn of SpaceX shares.

The extra $10bn raised, revealed in a statement by SpaceX announcing the completion of the listing, would by itself rank as one of the biggest IPOs in history.

It came thanks to a financial mechanism known as an overallotment option, more commonly referred to as a "greenshoe" option.

To prevent wild price swings and ensure a smoother launch, a greenshoe agreement lets the banks handling the listing sell more shares than originally planned.

In SpaceX's case, appetite was exceptionally high. The underwriters, which included Goldman Sachs, Bank of America, and JPMorgan, exercised the option in full, purchasing an additional 83.3 million shares directly from the company to meet the huge demand.

The listing also saw Musk elevated to trillionaire status, according to Bloomberg calculations.

And momentum behind SpaceX continued on Monday, with shares surging by more than 14% on their first full day of trading, to $184.

They were first offered to investors at $135, valuing the company at $1.8tn.

Because the vast majority of his wealth is directly tied up in SpaceX equity, his new milestone status remains entirely dependent on the market. A sharp decline in the stock could strip him of the title just as quickly as continued gains could multiply it.

The momentum showed no signs of slowing down as the new week opened. On its first Monday of market trading, SpaceX shares surged by over 14%, climbing to $184 (€158.62).

Analysts have warned SpaceX's the sky-high valuation leaves little room for error, raising questions over whether the loss-making company can sustain its current growth amid growing regulatory scrutiny and rising competition in the commercial space sector.