The rumor in China is that the new regulation is going to come out regardless - and Ma wanted to stop it from becoming reality - which make sense, large collateral will reduce profits of Ant, which primarily drive profit through consumer lending.
But why so late. Why let him do ipo up to the point that us$70m interest Ws lost to the investor doing margin to subscribe to ipo. (Margin needed as one want to max chance get a fee share. Not margin trading just in case.)
it is not as rational as one thinks. Something is going very serious wrong here. The regulation might be in the pipeline but if so any alert in the ipo on due diligence.
These might be a PR spin to cover up using a rational argument for some other things.
You're assuming "good faith" in listing risks in the IPO document :-) Companies generally list risks from the fear of being sued by shareholders, not from goodness of their heart. And recall this listing was not in the sue-happy jurisdictions like US.
His last ditch effort backfired spectacularly.