Nomura Holdings Inc.'s appointment of domestic brokerage head Koji Nagai as the new chief signals a retrenchment into its home market as Japan's biggest investment bank reels from the insider-trading scandal and losses abroad.

Nagai, 53, will succeed Chief Executive Officer Kenichi Watanabe, 59, next Wednesday, Nomura said Thursday. Watanabe and Chief Operating Officer Takumi Shibata, architects of the 2008 purchase of Lehman Brothers Holdings Inc.'s assets, will step down to atone for instances of staff leaking information about clients' share sales to traders.

The new CEO inherits the task of placating clients and regulators after the bank said Thursday that the leaks, which cost Nomura its top spot managing Japan bond sales, may have been more widespread than previously announced. The stock lost 83 percent during Watanabe's tenure as foreign operations, built with the Lehman assets, posted losses for a ninth quarter.