Australian investment bank Macquarie Group and Switzerland's UBS AG have successfully raised $521.2 million in an initial public offering for insurer Cover-More Group. Cover-More's listing is the third-biggest IPO of the year.

According to a report by news daily The Australian, the two investment banks have already closed the book build. Macquarie and UBS are in the midst of allocating to investors a small portion of the 260.6 million shares of the travel insurer and medical assistance company.

Cover-More shares are priced at $2 apiece. Most of the shares had already been sold to fund managers before the IPO's prospectus was issued earlier this month. Cover-More is expected to start trading on December 23, the report said.

This so-called cornerstone process enabled the IPO to be fully underwritten while allowing Macquarie and UBS to claw back some shares. This also enabled the two banks to sell the shares to inividual investors and select institutional clients, The Australian said.