Nomura Holdings Inc. shareholders should vote against the reappointment of its long-standing chief executive officer after Japan's biggest brokerage was penalized for leaking market-sensitive information, according to Institutional Shareholder Services Inc.

CEO Koji Nagai "should be held responsible for the information leakage incident" and so his re-election to the board isn't warranted, the influential proxy adviser wrote in a report on its recommendations for voting at Nomura's annual shareholder meeting scheduled for June 24.

Japan's financial regulator ordered Nomura to improve internal controls last month following revelations that its employees leaked nonpublic information on potential changes to listing criteria on the Tokyo Stock Exchange. The firm was dropped from bond deals and missed out on a key role managing a $12 billion equity offering in the wake of the incident. Nagai, 60, took a 30 percent pay cut for three months, but vowed to stay on as CEO.