Sumitomo Mitsui Financial Group Inc. SMFG announced Thursday that it would increase its ownership stake of investment bank Jefferies Financial Group Inc. JEF from 4.5% to 15% as part of a planned extension of the corporate-investment banking relationship the two firms signed in 2021. Sumitomo Mitsui Financial Group Inc. SMFG said Thursday it will increase its ownership stake in investment bank Jefferies Financial Group Inc. JEF to 15% from 4.5% as part of a planned expansion of the corporate and investment banking relationship that both firms signed in 2021. SMBC will ask Jefferies shareholders to approve a new non-voting class of common shares. This is in order to increase its ownership of Jefferies by direct and indirect purchases of Jefferies common stock on the open market.