Japan Exchange Group Inc. said Monday it has named Hiromi Yamaji, who heads its Osaka bourse unit, as the new president of the Tokyo Stock Exchange operator, which has been struggling to restore investor trust following an unprecedented full-day trading suspension.

Yamaji, 65, will assume the post on April 1, replacing Akira Kiyota, the chief executive of Japan Exchange Group who currently doubles as head of Tokyo Stock Exchange Inc., after the worst outage in the bourse's history on Oct. 1 led to the resignation of then-President Koichiro Miyahara the following month.

The system failure also stopped all trading of equities listed on stock exchanges in Sapporo, Nagoya and Fukuoka.

Yamaji started his career with Nomura Securities Co. in 1977 after graduating from Kyoto University. He assumed the presidency of the Osaka unit in 2013 when Japan Exchange Group was created through the merger of the operators of the Tokyo and Osaka bourses.

Moriyuki Iwanaga, senior executive vice president of Japan Securities Clearing Corp., will succeed Yamaji as president of Osaka Exchange Inc., the parent company said.