Mizuho Securities Co. said Wednesday online trading in stocks for its customers was suspended for several hours due to a glitch.
The securities unit of Mizuho Financial Group Inc. is trying to identify the cause of the trouble, which occurred in the morning and lasted until it resumed the service around 12:30 p.m.
Some customers of the service were not able to see their asset balances, according to the brokerage. The Japanese financial group has been hit by a series of system problems in recent months that have undermined public confidence.
Its banking unit, Mizuho Bank, one of Japan's three major banks, temporarily suspended around 80% of its automated machines nationwide due to a system glitch in late February.
In March, a hardware problem caused a delay in foreign currency-denominated remittances, mainly for corporate customers.