Mizuho's eight system failures in 2021 drew two FSA orders and resignations

Mizuho Bank — one of Japan's largest banks — suffered seven computer system failures between February and September 2021, then an eighth in late September. The Financial Services Agency said the failures 'caused significant influences on individual and corporate customers' and issued business improvement orders to Mizuho Bank and its holding company on September 22, 2021.

The problems came after Mizuho fully switched to its Minori core system, in which it had invested about 400 billion yen ($3.5 billion). According to the Asahi Shimbun, an executive with little experience was put in charge of the systems department after the renewal and department staff were cut by 60 percent. The FSA concluded that management neglected its duty to be prepared for glitches.

A second business improvement order followed on November 26, 2021, covering the full series of failures since February 28, including an incident in which Mizuho skipped part of required sanctions pre-screening to speed a transfer. Mizuho apologized for 'allowing these system failures to occur repeatedly in a short period of time' and was ordered to submit a business improvement plan and clarify management responsibility by January 17, 2022.

Eight glitches in 2021 after a ¥400B ($3.5B) core-system renewal; FSA issued two business improvement orders and top executives resigned.

After the ¥400B core renewal, systems-department staff were cut 60% and an inexperienced executive took charge.

Repeated failures showed the renewal did not include the operational capacity to run and maintain the new system.

Mizuho skipped legally required sanctions checks under operational pressure, compounding the technical failures.

Management treated systems as a cost to minimize rather than infrastructure whose failure hits millions of customers.

Cutting systems staff and rushing core renewals to save money turns routine maintenance into national-scale outages; resilience must be funded before the failure, not after.

In November 2021, Mizuho Financial Group president Tatsufumi Sakai and Mizuho Bank chief executive Koji Fujiwara decided to step down over the recurring glitches. The FSA's second order demanded a business improvement plan, management accountability and quarterly progress reports, and the bank remained under regulatory supervision as it rebuilt systems governance. The episode became a benchmark in Japan for the risks of aggressive cost-cutting and rushed core-banking renewals at systemically important banks.