Market leader

Japanese / English

Bar admissions:

New York



Practice areas:

Capital markets

Katsumasa has been recognized as a top-tier lawyer in capital markets, M&A and corporate crisis/governmental investigation areas, but recently has become active in contentious matters as well, particularly those relating to activist shareholders and other capital markets and M&A matters.

He is a lawyer qualified in Japan and NY and a certified member of the Securities Analysts Association of Japan. His thorough knowledge of business, accounting and markets, together with plentiful experience in various kinds of deals and legal matters, enable him to provide uniquely valuable legal and strategic advice to his clients.

He has been selected as a leading lawyer in Japan by major publications including WWL, Chambers, Legal 500, IFLR, asialaw and Best Lawyers, and ranked as a top-ten outstanding FT Asia-Pacific Innovative Lawyers Report by the Financial Times in 2016 (as the first-ever lawyer with the honor in Japan).

He publishes various articles relating to capital markets and M&A, which lead new regulations and practice. Recently, he has taken the initiative to introduce SPACs to Japan through frequent discussions with regulators, media, investment banks, venture capitalists and other market participants.

Katsumasa has been a member of the Securities Law Committee of the International Bar Association since 2018 (Chair of the M&A sub-committee from 2018 to 2019, Chair of Public Company Practice and Regulation subcommittee from 2020 to 2021, Deputy Conference Quality Officer from 2022 to 2023 and Chair of the M&A sub-committee from 2023).

He heads the capital markets practice group at MHM and leads the group with a mission of contributing to the growth of capital markets in Japan and Asia in the best interests of our clients.

  • Global offering of Japan Post Bank (2023)
  • Global IPO of Socionext (2022)
  • Joint Venture between TSMC and Sony (2021)

  • Capital markets
  • M&A
  • Crisis management
  • Litigation

  • Banking
  • Financial services
  • Consumer goods and services
  • Industrials
  • Media

  • Charterd Member of the Security Analysts Association of Japan (2006-)
  • Officer of Securities Law Committee of International Bar Association (2010-)

  • Keio University (LL.B., 1998)
  • Columbia University School of Law (LL.M., 2004)