Kakao Pay Corp, backed by Chinese e-commerce firm Ant Group, was planning to offer 17 million new shares next month in an indicative range of 63,000-96,000 won each, giving it a market valuation of up to 12 trillion won.
But the Financial Supervisory Service (FSS) said in a regulatory filing it had asked the company to resubmit its IPO registration statement to answer questions about its prospectus for the Seoul listing.
FSS did not give details but said the IPO registration statement fell into one of three categories: having an incorrect format; containing false information or omitting important facts; or containing unclear statements that could mislead investors.
The fintech firm, a unit of South Korea's top mobile messaging service company Kakao Corp, provides financial services including money transfers, savings accounts and asset management.
Under South Korean regulations, failing to revise the registration statement within three months would result in the initial statement being withdrawn.
In June, FSS asked game developer Krafton Inc to revise its IPO registration statement, which led the video game maker to cut its IPO target by almost a quarter.
Kakao Corp is the largest shareholder in Kakao Pay Corp, with 55%, followed Ant Group's Alipay with 45%, the regulatory filing showed.
($1 = 1,140.6000 won)
(Reporting by Heekyong Yang; Editing by Edmund Blair)