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Mizuho Securities

A Japanese investment banking and securities firm wholly owned by Mizuho Financial Group.

Last updated October 13, 2026

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Overview

Mizuho Securities Co., Ltd. is the securities and investment banking arm of Mizuho Financial Group, one of Japan’s major financial groups. The company provides securities brokerage, capital-markets services, underwriting, corporate finance, advisory work, research, and trading-related services to institutional investors, corporations, public-sector entities, and other financial institutions. Its activities cover both debt and equity markets, including bond and stock trading, debt and equity financing, structured-finance advisory, and the publication of research and ratings on publicly traded companies. The current company was created on 7 May 2009 through the merger of Shinko Securities and the former Mizuho Securities. The transaction had been delayed by the global financial crisis that began in 2008. The surviving legal entity was the former Shinko Securities, which adopted the Mizuho Securities name after the merger. Following the combination, Mizuho Financial Group held 59.51% of the securities company, making it a core component of the group’s capital-markets franchise. Mizuho Securities is now described as a wholly owned subsidiary of Mizuho Financial Group in the reference material, although the historical merger account records the 59.51% post-merger stake. The company’s predecessor businesses developed a significant position in Japan’s securities industry. During the early 2000s, Mizuho Securities was regarded as one of the four large firms controlling a substantial share of Japanese trading activity. In addition to its domestic securities business, the organization operates international subsidiaries, including Mizuho Securities USA. The business serves clients that require access to Japanese and international markets, investment-banking advice, securities execution, financing, underwriting, and institutional research. Mizuho Securities’ history also includes a major operational and legal incident. In December 2005, an employee entered an erroneous sell order involving shares of J-COM Co., Ltd. on the Tokyo Stock Exchange. The order could not be canceled because of a fault in the exchange’s computer system, producing an approximately ¥40.7 billion loss for Mizuho Securities. The company subsequently pursued damages against the Tokyo Stock Exchange and was awarded approximately ¥10.7 billion. The episode became a notable example of the operational, technology, and risk-management exposures associated with electronic securities trading. The brand’s market position is based on its connection to Mizuho Financial Group, its broad Japanese securities platform, and its ability to combine brokerage, underwriting, research, financing, and advisory capabilities. It is primarily a business-to-business financial-services brand rather than a consumer-facing retail brand, with institutional and corporate relationships forming the center of its activities.

History

Mizuho Securities combines the histories of Shinko Securities and the former Mizuho Securities. Before the 2009 combination, the former Shinko Securities was an equity-method affiliate of Mizuho Financial Group, while the former Mizuho Securities was a consolidated subsidiary. The planned merger was postponed during the 2008 financial crisis and was completed on 7 May 2009. The surviving company was the former Shinko Securities, which changed its name to Mizuho Securities. Mizuho Financial Group held 59.51% of the post-merger company according to the historical account. The predecessor businesses established a broad presence in Japan’s securities markets. During the early 2000s, Mizuho Securities was considered one of the four major firms with substantial control over Japanese trading activity. Its business covered stock and bond trading, debt and equity financing, structured-finance advisory, corporate and institutional investment banking, and research on publicly traded companies. Its customers included financial institutions, public corporations, institutional investors, and other firms. The group also developed international operations, including Mizuho Securities USA. A defining event in the company’s history occurred in December 2005, when an employee placed an erroneous sell order for J-COM shares on the Tokyo Stock Exchange. Because of a fault in the exchange’s computer system, the order could not be canceled. The resulting loss was approximately ¥40.7 billion. Mizuho Securities brought a damages case against the exchange and was awarded approximately ¥10.7 billion. The episode highlighted the importance of trading-system reliability, order controls, and operational risk management in electronic securities markets. Following the 2009 merger, Mizuho Securities became the principal securities platform within Mizuho Financial Group. Its role is to connect the group’s corporate, institutional, and financial-institution clients with securities markets and investment-banking services. The available reference material does not provide a sufficiently detailed account of later product launches, leadership changes, financial performance, or current organizational developments.

  • 2009

    Merger creates the current Mizuho Securities

    [1]

    Shinko Securities and the former Mizuho Securities merged on 7 May 2009, with the surviving company taking the Mizuho Securities name.

  • 2005

    J-COM trading-order incident

    [1]

    An erroneous J-COM share sell order and a Tokyo Stock Exchange system fault produced an approximately ¥40.7 billion loss for Mizuho Securities.

  • 2005

    Damages awarded in exchange-system case

    [1]

    Mizuho Securities received an approximately ¥10.7 billion award in its damages case against the Tokyo Stock Exchange.

  • 2004

    Polaris Capital Group divested

    [1]

    The Polaris Capital Group was divested as the business focused on private-equity investment.

Products and positioning

A major Japanese securities and investment-banking platform associated with Mizuho Financial Group, serving corporations, financial institutions, public entities, and institutional investors.

  • Brokerage

    Equity brokerage and trading

    Services for trading and handling listed shares, including access to Japanese equity markets for institutional, corporate, and other eligible clients. The business also supports market information and research related to publicly traded companies.

  • Capital markets

    Fixed-income and bond services

    Bond trading and related fixed-income activities form part of the company’s securities-market offering. These services support clients seeking to issue, buy, sell, or manage exposure to debt instruments.

  • Investment banking

    Debt and equity financing

    The company supports corporate and institutional financing through debt and equity-market transactions. This includes assistance with securities issuance and access to capital markets.

  • Advisory

    Structured-finance advisory

    Advisory services related to structured finance are provided to financial institutions, corporations, public entities, and other sophisticated market participants requiring customized financing solutions.

  • Investment banking

    Corporate and institutional advisory

    Mizuho Securities advises corporations and institutions on investment-banking matters, including capital raising and mergers and acquisitions. The available reference material identifies advisory work as a core business but does not detail individual mandates.

  • Research

    Equity research and ratings

    The firm issues buy and sell ratings for publicly traded stocks and produces research intended to inform institutional and professional-market participants.

Controversies

  • 2005

    J-COM erroneous-order incident

    In December 2005, a Mizuho Securities employee entered an incorrect sell order for J-COM shares on the Tokyo Stock Exchange. A fault in the exchange’s computer system prevented the order from being canceled, leading to an approximately ¥40.7 billion loss. Mizuho Securities later obtained an approximately ¥10.7 billion damages award in litigation against the exchange.

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Brand decisions

  • 2009

    Merger of Shinko Securities and the former Mizuho SecuritiesM&A

    Background

    Mizuho Financial Group sought to combine its securities businesses. The transaction was postponed during the 2008 financial crisis before being completed in May 2009.

    Action taken

    Shinko Securities merged with the former Mizuho Securities on 7 May 2009. The surviving legal entity changed its name to Mizuho Securities.

    Aftermath

    The merger created the current Mizuho Securities and consolidated the group’s securities and investment-banking platform. Mizuho Financial Group held 59.51% of the post-merger company according to the historical reference.

Recent events

  • Albemarle prices public stock offering[2]

    Reported:

    Albemarle announced the pricing of an underwritten public offering of 8,496,733 common shares at $153 per share. The offering was expected to close on or about February 8, 2021, subject to customary closing conditions.

Sources2 sources

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