Mizuho Financial : (Updated) Submission of Business Improvement Plan

January 24, 2022

Company: Mizuho Financial Group, Inc.

Representative: President & Group CEO Tatsufumi Sakai

Head Office: 1-5-5 Otemachi, Chiyoda-ku, Tokyo

Stock code: 8411 (First Section of Tokyo Stock Exchange)

Company: Mizuho Bank, Ltd.

Representative: President & CEO Koji Fujiwara

Head Office: 1-5-5 Otemachi, Chiyoda-ku, Tokyo

(Updated) Submission of Business Improvement Plan

Mizuho Financial Group, Inc. and Mizuho Bank, Ltd. hereby announces that there have been corrections made to the above-mentioned disclosure material released on January 17, 2022, at 15:20 p.m. (JST).

1. Reason for corrections
   To correct the discrepancies between the English version and the original Japanese version, and typographical errors.
2. Content of Corrections

Please see the following pages. Revised parts are underlined.

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January 17, 2022

Company: Mizuho Financial Group, Inc.

Representative: President & Group CEO Tatsufumi Sakai

Head Office: 1-5-5 Otemachi, Chiyoda-ku, Tokyo

Stock code: 8411 (First Section of Tokyo Stock Exchange)

Company: Mizuho Bank, Ltd.

Representative: President & CEO Koji Fujiwara

Head Office: 1-5-5 Otemachi, Chiyoda-ku, Tokyo

Submission of Business Improvement Plan

Today, Mizuho Financial Group, Inc. and Mizuho Bank, Ltd. submitted a business improvement plan to the Japanese Financial Services Agency based on the business improvement order issued on November 26, 2021.

Regarding the recent series of IT system failures that began from February 28, 2021, as a financial institution bearing responsibility for maintaining societal infrastructure, we deeply apologize for the inconvenience and concern we have caused to our customers and society by allowing these system failures to occur repeatedly in a short period of time and, as a consequence, failing to adequately fulfill our role in facilitating smooth settlements.

In the business improvement plan we submitted today, we have fully assessed and revised the measures for improving IT systems that we have formulated up until now, as well as our measures for customer relations and crisis management. In designing the plan, we gathered feedback from frontline offices and also sought out external viewpoints and expert insights in order to ensure the effectiveness, completeness, and continuity of the plan. Following this assessment and revision, we will continue to steadily implement our measures to prevent further incidents and further enhance our multilayered system failure response capabilities.

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Also, to strengthen governance throughout the entire group, we have formulatedmeasures on business strategy and corporate resource allocations based on an assessment of the on-the-ground situation, strengthen our internal management structure for IT system risk management and legal and regulatory compliance, and further enhance our supervisory functions, in line with the roles and functions of Mizuho Financial Group and Mizuho Bank.

Furthermore, we will take measures to enhance our frameworks for our people and organization and reform our corporate culture. This will serve as the foundation for enhancing the effectiveness and sustainability of our measures to prevent further incidents and our corporate management.

Both Mizuho Financial Group and Mizuho Bank are steadily implementing business improvement plans to prevent such a situation from happening again. In order to ensure that customers can use Mizuho services with peace of mind, all directors and employees will work together as an organization to establish a strong framework that prevents system failures from having a significant impact on customers and that minimizes the impact on customers even in the event of a failure. We will continue to pursue these initiatives under our current ever- changing environment.

As announced on June 15, 2021, Mizuho Financial Group and Mizuho Bank have established the System Failure Response Evaluation Committeeon the supervisory side and the System Failure Improvement Promotion Committeeon the business execution side, to follow up on, review, and revise the business improvement plan. We will continuously verify the progress of measures to prevent further incidents through both of these perspectives.

Please refer to the attachments for an overview of the business improvement plan.

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Attachment 1

Note: [ ] indicate implementation timelines. [Added] indicates measures added since the review of measures to prevent further incidents released in June.

Mizuho Bank Business Improvement Plan

I. Enhancement of multilayered system failure response capabilities

i) Measures to improve IT systems

1. Assessments and other efforts to prevent system failures

(1) Inspection of application

1. Check that the quality remains the same as at the time of the initial decision for release, add the targeted transaction services, and implement confirmation testing for non-operating services. [Completed]
2. Confirm the ripple effects of and measures for errors that could lead to severe failures.
3. • Develop a system operation check to verify MINORI's operations when severe failures occur and formulate an IT system support plan. Implement IT system support based on the results of the system operation check. [Completed]
   • Use a testing environment to run a test deliberately causing system errors with the potential to be severe failures for mission-critical systems. Confirm ripple effects on MINORI and other peripheral systems. [September 2022]
4. Assess maintenance necessary to stable operation.
5. • Assess maintenance necessary to MINORI's stable operation, including the effects an increase in transactions would have on systems, the need for responses, and similar. [Beginning March 2022]
   • Share details on assessments of the status of IT system processing and other factors. Conduct assessments and verifications of system specifications and potential risk events. [Added] [June 2022]

1. Inspection of foundational infrastructure
2. 1. Handling and inspection of firmware
       Address and inspect firmware from time of system failures. Inspect for

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similar potential issues. [Completed]

1. 1. Management of maintenance terms
   2. • Identify hardware that must be upgraded within the maintenance term and inspect for hardware that is beyond the maintenance term. [Completed]
        Formulate an IT system support policy based on the results. [March 2022]
        Expand the scope of inspections. [March 2022]
      • Develop framework for review of hardware upgrades. [Added][Completed]
        Expand scope of hardware that must be upgraded within the maintenance term. [March 2022]
   3. Clarification of matters for managing information and methods for software bugs [Added]
   4. • Clarify regulations on bug-relatedinformation. [Completed] Implement framework foranalyzing bug-relatedinformation. [March 2022]
   5. Enhancement of early warning indicator management and preventative maintenance [Added]
   6. • Implement regular inspections to improve management of hardware. [April 2022]
      • Implement preventative maintenance of critical hardware. [Completed]
        Implement disk component inspections for preventative maintenance. [March 2022]
        Formulate an inspection plan for disk components in additional critical hardware. [March 2022]
        Regulate inspections of disk components for preventative maintenance of critical hardware. [March 2022]
   7. Securing effective operation of IT systems [Added]
   8. • Formulate a plan for inspections checking thatfoundational infrastructure is operating according to requirements, and implement inspections in upstream systems. [March 2022]
        Formalize in regulations. [June 2022]
2. Enhancement of framework for development projects

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