Hana Financial Group Chairman Ham Young-joo / Courtesy of Hana Financial Group

Hana Financial Group, one of South Korea’s major banking groups, said Friday it has decided to buy a stake in the country’s top crypto exchange operator Dunamu for 1 trillion won ($669 million), the largest-ever investment by a bank into a virtual asset operator.

In a regulatory filing, Hana Financial said its flagship Hana Bank will take over a 6.55 percent stake in Dunamu, the operator of Upbit, from Kakao Investment.

Hana Financial will become the fourth-largest shareholder after the stake takeover.

The alliance between an established financial institution and a virtual asset operator heralds their business cooperation going beyond simple services, such as a…