The Tokyo Stock Exchange Group Inc.'s second major system error in seven months took derivatives trading offline for 95 minutes and underscored the challenge Japan faces to revive its reputation as a global equity hub.

Share trading volumes fell, government bonds dropped and index-futures traders were diverted to Tokyo's smaller Osaka rival during the halt, which lasted from 9:22 a.m. to 10:55 a.m. local time. The error was compounded by a failure of backup systems similar to that which caused the biggest disruption in six years on Feb. 2, said Hiroaki Uji, director of trading systems at the bourse.

The outage, which affected stock-index and government-bond futures and options, is a further setback for the Tokyo exchange as it pursues a takeover bid for the Osaka bourse, which dominates Japan's equity derivatives business. The breakdown also highlights the vulnerability of global markets to computer malfunctions, a week after errors at market-maker Knight Capital Group Inc. (KCG) led to wrong trades for more than 100 U.S. stocks.