South Korea’s government sees tech firms as the new chaebol

A FEW MONTHS ago Kim Beom-su looked like the face of responsible capitalism in South Korea. In March the billionaire founder of Kakao, which runs the country’s most successful messaging app and a slew of other digital services, promised to give away half his wealth for charitable causes, the second Korean tycoon to make that pledge. Now he is making headlines for some less salubrious reasons. Antitrust officials have reportedly set their sights on his private holding company for allegedly failing to report properly on its shareholders and affiliates.

The apparent move against Kakao’s founder is the latest salvo in an ongoing battle. Like their counterparts in America and China, South Korea’s technology giants have come under scrutiny. Officials worry that as firms such as Naver, which began life as a search engine, and Kakao have expanded into anything from ride-hailing to personal finance, they have picked up the bad habits of the chaebol. These sprawling conglomerates were instrumental in making South Korea rich and continue to dominate its economy. But they are notorious for murky governance structures, oligopolistic business practices and close ties with the political elite.

Over the past few weeks politicians have ramped up the rhetoric. “Kakao has turned from a symbol of growth and...