China warned Jack Ma and senior Ant Group Co. executives that the fintech giant will face new curbs on its expansion, highlighting growing regulatory risk for the world’s largest initial public offering just days before its trading debut.

Ma, Ant’s billionaire co-founder and one of China’s most powerful businessmen, was summoned to a rare joint meeting on Monday with the country’s central bank and three other top financial regulators. While neither side disclosed details of what was discussed, people familiar with the matter said Ant’s leadership team was told the company will face increased scrutiny and be subject to restrictions on capital and leverage similar to banks.

Investors have long understood that Ant would fall under new Chinese regulations on financial conglomerates, but the meeting may nonetheless temper the frenzy surrounding history’s biggest stock-market debut. Ant is due to start trading on Thursday after raising at least $34.5 billion in an IPO that attracted more than $3 trillion of orders from retail investors in Shanghai and Hong Kong.