Mizuho Financial Group Inc. is increasing its pool of bankers who advise small Japanese businesses on matters ranging from investing to going public as part of a push to spur fee income at the nation's third-biggest banking group.

Tokyo-based Mizuho seeks to boost the number of bankers covering small and midsize enterprises, or SMEs, by about 50 percent in the next three years from the current 350, said Hidetoshi Kaji, a senior corporate officer at its securities unit. It will do so mainly by transferring people from its retail brokerage and filling the gap by hiring new graduates.

Chief Executive Officer Yasuhiro Sato has been stressing the importance of bolstering fee businesses as plummeting interest rates curtail profitability from lending. Japanese SMEs, which earned record profits last year, are paying fees for advice on anything from investing in a negative-rate world to pursuing acquisitions and listing shares amid the global market turmoil.