Australia's biggest retail brokerage is keeping its call centre open overnight as tens of thousands of investors wait to see their allocation for the world's biggest-ever initial public offering.
Elon Musk's SpaceX will go public on the US Nasdaq exchange on Saturday morning, Australia time, after raising $US75 billion ($A106 billion) to advance Elon Musk's grandiose vision of making human life multi-planetary.
Commonwealth Bank's CommSec share-trading platform said its contact centre would be open overnight Friday until 6am, and then again from 9am to 5pm on Saturday to respond to queries related to the IPO.
Reuters reported on Wednesday the float was nearly four times oversubscribed, meaning that would-be investors would likely have their allocations scaled back and offered refunds.
On social media one Australian user posted that based on the amount debited from his CommSec account, it seemed he had only been allocated 10 per cent of the SpaceX IPO he had requested.
Others were still waiting Friday for official confirmation.
CoomSec said it would put messaging up on its app and website when shares were allocated, and an email would be sent to every applicant.
A source familiar with the transaction but not authorised to speak publicly told AAP there had been applications from superannuation funds and institutional investors, along with tens of thousands of Australian retail investors.
"I think that was really healthy, healthy levels of interest, certainly by the number of applications, and I think very healthy levels of demand," he said.
The source said it was probably the most in-demand IPO in Australia since Medibank Private's 2014 float, which raised $5.7 billion for the federal government.
Retail investors in Australia and a number of other countries outside the United States, including Canada, the UK, Japan and in the eurozone, were offered access to the IPO in what was perhaps an unprecedented move.
SpaceX shares were being offered at $US135 ($A191) apiece, giving the space exploration company a mammoth $US1.75 trillion ($A2.5 trillion) valuation - among the 10 most valuable companies in the world.
The shares will begin trading on the Nasdaq under the ticker symbol SPCX at 9.30am New York time (11.30pm AEST).
Because of special rights attached to his shares, Mr Musk will retain 82 per cent of voting power in SpaceX even after the float, which has made him the world's first trillionaire.
