These structural features mean that The Hut Group will not be granted a so-called premium listing and will not be eligible for the FTSE 100 despite being big enough for the blue-chip index.
Despite these concerns BlackRock, Henderson Global Investors, Merian and the Qatar Investment Authority agreed to buy £565 million of the shares offered.
While private equity owner KKR is selling its entire stake worth £448 million.
Michael Hewson, analyst at CMC Markets, said: “As the biggest IPO since Royal Mail was launched back in 2013 The Hut Group will be closely scrutinised in terms of not only early demand, but also the sustainability of the business model.
“Time will tell as to whether the valuation is a solid one, or whether KKR has made the right move in selling out of their entire stake."