HONG KONG (Reuters Breakingviews) - When future business school students tackle the case study of Ant and the Curse of the Mega-IPO, it will be clearer what led to the shock suspension of the Chinese financial group’s record-shattering $37 billion initial public offering a mere 36 hours before its shares were due to begin trading. In the meantime, Ant founder Jack Ma can perhaps console himself with the thought that other big companies have faced difficult market debuts but gone on to trade perfectly happily. Regulators in Shanghai on Tuesday night suspended Ant’s $17.5 billion listing on the local STAR market due to concerns that looming changes in online lending regulations, published the previous day, might cause the company to fall short on its disclosure requirements. Ma and other Ant executives had met with financial regulators on Monday in what appeared to be a dressing down following the technology tycoon’s comments disparaging global financial regulation. Ant then halted its Hong Kong listing. Large stock sales rarely run smoothly, although few have suffered something this out-of-the-blue. A debut day trading glitch marred Facebook’s $16 billion float in 2012; it was 14 months before the social network’s shares recovered their issue price. Oil giant Saudi Aramco, whose $29 billion 2019 offering was the world’s largest until Ant came along, cut its valuation and abandoned plans for multiple listings before listing on its home exchange. Perhaps Ma, who charmed investors for e-commerce giant Alibaba’s $25 billion float in 2014 and had attracted mind-boggling amounts for Ant’s offering, thought he was immune to such risks. Few companies would try pricing an IPO in the unpredictable last days of a U.S. presidential election campaign. Whatever happens next, the suspension does not reflect well on mainland Chinese stock markets. It’s particularly strange that regulators whose main concern is preserving financial stability would cause such unexpected last-minute ructions for a company which handles more than half of China’s online payments. The confusion could benefit Hong Kong if more Chinese companies choose to list in the former British colony. Ant has apologised to investors and pledged to work closely with regulators. That is about all it can do right now. Many mega-IPOs have overcome early setbacks. But right now, the damage to Ant – and to China as a venue for large-scale corporate fundraising - has been done.