Sumitomo Mitsui Financial Group Inc., Japan's second-largest bank by market value, is in talks with Daiwa Securities Group Inc. to raise its stake in their investment banking joint venture, two sources said.

Sumitomo Mitsui is negotiating to raise its stake from 40 percent to a majority position, said the sources, who declined to be identified because the matter is private.

Chika Togawa, a spokeswoman for Tokyo-based Sumitomo Mitsui, declined comment, as did Daiwa spokesman Yukiko Kishino.

Sumitomo Mitsui is seeking to increase its stake in Daiwa SMBC to as much as 67 percent, the Yomiuri newspaper reported earlier Wednesday, without saying where it obtained the information.