Kim Beom-su, the founder of the company behind South Korea’s most popular messaging app KakaoTalk, is now the richest person in the country, according to the Bloomberg Billionaires Index on Friday.

Kim has seen his fortune reach $13.4 billion this year, surpassing Samsung Electronics Vice Chairman and de-facto leader Lee Jae-yong, whose net worth was estimated at $12.1 billion.

Kim’s assets grew by $6 billion in 2021 alone as Kakao shares soared 91 percent, boosted by the stock market debuts or debut plans of its several subsidiaries.

Bloomberg said that Kim’s case is an example of how self-made technology entrepreneurs are climbing the superrich list in South Korea, overtaking members of families that control the country’s decades-old conglomerates.

Kim, 55, born as the third of five children in a poor family, grew up in a small one-bedroom apartment. His parents reportedly earned their living mainly through manual labor jobs and he was the only child who made his way into a university.

After working five years at Samsung SDS, an IT services affiliate of Samsung Electronics, Kim opened a PC cafe and later founded an online game platform operator, Hangame Communications, which was eventually merged with search engine Naver to become the country’s dominant web portal, NHN.

In 2010, Kim and his startup firm launched KakaoTalk, which soon became the country’s dominant messaging app.

Over the past decade, Kakao has grown fast. As of Friday, Kakao and its two listed affiliates marked an aggregate market cap of 73 trillion won.

Kim, who now serves as the board chairman at Kakao, holds around 24 percent of Kakao’s shares, including the ones he owns through K Cube Holdings, Kim’s fully owned investment firm, according to a regulatory filing in May.

In February, he pledged to donate more than half of his assets. In the following month, he joined the Giving Pledge, a global campaign created by Bill and Melinda Gates and Warren Buffett for the world‘s wealthiest individuals to give back the majority of their wealth.