Citigroup Inc. plans to give Sumitomo Mitsui Financial Group Inc. the right of first refusal this month to buy its Japanese consumer-banking business, said people with knowledge of the matter.

Sumitomo Mitsui’s lending arm is in talks with Citigroup to purchase the retail bank for about $345 million, said the people, who asked not to be named because the discussions are private. Sumitomo Mitsui Banking Corp. would retain all of Citigroup’s retail bank staff and branches in Japan, the people said.