Sumitomo Mitsui Financial Group Inc. will announce an agreement to buy Citigroup Inc.'s Japanese consumer-banking business as soon as next week, sources with knowledge of the matter said.

The lending unit of Japan's second-biggest bank by market value will purchase the operations from Citibank Japan Ltd. for about ¥40 billion ($330 million), according to the sources, who asked not to be named as the discussions are private.

Sumitomo Mitsui Banking Corp. is one of at least five banks that began bidding for the assets in September, as Citigroup sells off consumer-banking operations around the world to focus on faster-growing markets. The Japanese lender is seeking to get more business from wealthy individuals in a country with about $14 trillion in household financial assets.