Mizuho Financial Group Inc. is in final talks to buy a stake in Joint-Stock Commercial Bank for Foreign Trade of Vietnam for as much as ¥60 billion, a source said.

Mizuho Corporate Bank Ltd., a unit of Japan's third-biggest bank by market value, is seeking as much as 20 percent of the Hanoi-based lender known as Vietcombank, the source said on condition of anonymity before a deal is struck. The transaction may be completed by next month, the source said.

Foreign banks are investing in Vietnam to tap demand for credit in the Southeast Asian nation even as it struggles to contain inflation nearing 21 percent. Commonwealth Bank of Australia and Singapore's United Overseas Bank Ltd. won approval to raise their stakes in Vietnamese banks earlier this month.