* Kakao Bank trading at 65% above IPO price * The purely digital bank gained $25 bln in assets in four years * “It’s a platform, not just a bank” - analyst (Adds business plans, IPO prospects for Kakao Pay) SEOUL, Aug 6 (Reuters) - Digital lender Kakao Bank Corp made a stunning debut on Friday, surging 65% from its IPO price to become South Korea’s biggest financial services firm by market value. The country’s first purely mobile bank to go public is expected to capitalise on rare growth opportunities for a financial firm afforded by an unusual South Korean regulatory framework. Due to its large user base, Kakao Bank is able to recommend and collect fees on products offered by other financial firms on a much bigger scale than many traditional lenders, and also has an advertising business. “Shareholders are bullish as it’s a platform, not just a bank,” said Seo Young-soo, an analyst at Kiwoom Securities. Its shares were changing hands at 64,600 won in late morning trade on Friday, compared with its IPO price of 39,000 won and valuing it at roughly $26 billion. By contrast, KB Financial Group Inc, South Korea’s biggest traditional financial group, was worth about $19 billion. Kakao Bank became profitable in 2019 after less than two years in operation and has 13.35 million monthly active users, making it the largest financial app in the country. “It’s the only purely mobile digital bank in the world that has grown into a large bank with 28.6 trillion won ($25 billion) in assets in just four years,” said Seo. The bank raised some $2.2 billion in its IPO and plans to use the proceeds to expand its platform-related businesses, which still only account for 6% of its income. Three-quarters of the 804.2 billion won it made in operating profit last year was interest income. It currently offers personal credit loans and loans for the lump sums that Koreans must provide upfront when renting a property, and plans to expand into mortgages and loans to small businesses. The listing is the country’s biggest since game company Netmarble’s IPO raised 2.7 trillion won in 2017, continuing a bumper year for South Korean stock market floats although some valuations have been slashed in recent offerings. Kakao Corp, operator of South Korea’s dominant chat app and Kakao Bank’s top shareholder with a 27.3% stake, is also planning to take its payments affiliate public. But Kakao Pay, which is also backed by China"s Ant Financial, has been asked by financial authorities to resubmit here its IPO registration statement. Prior to that request it had been seeking to raise up to $1.4 billion for a market valuation of as much as 12 trillion won. ($1 = 1,143.1100 won)