Japan's alternative trading platforms missed out on a potential payday as regulators stopped them from fielding orders when a computer error caused the biggest trading disruption in six years Thursday at the Tokyo Stock Exchange.

The glitch at the TSE disabled trading of 241 issues for three hours. Japan's biggest bourse hasn't yet been able to measure the impact on trading, Chief Information Officer Yoshinori Suzuki said Thursday in Tokyo.

The Japan Securities Dealers Association shut trading on alternative platforms SBI Japannext and Chi-X Japan on concerns that shares couldn't be priced fairly without the main bourse, said spokesman Atsushi Sakiyama.