Chair of the Japanese Services group, Mari Yamamoto Regnier represents public and privately held Japanese businesses in the U.S. and their parent companies and affiliates in Japan. Mari offers a unique ability to navigate the differences between Japanese and American business, along with bilingual language skills and a multicultural background that allow her to provide solutions that are actionable for both paradigms.
Advising on corporate matters of all kinds, Mari guides clients to work through complex mergers and acquisitions, joint ventures, supply chain management, management counseling, global human resources, antitrust and competition law matters, and other business transactions. She also provides strategic counsel in litigation and compliance matters involving Japanese companies.
A native of Japan, Mari began her career as the firm’s first Japanese services coordinator, where she was instrumental in locating and acquiring industrial sites for major automotive plants. Mari has a deep understanding of and appreciation for Japanese culture, and is bilingual, making her invaluable when advising clients to build strong workforces and expand Japanese businesses internationally.
In addition, Mari provides management training in Japan and the U.S. She covers trends in M&A and litigation, best practices for compliance and explains the implications of U.S. antitrust laws on Japanese companies. She is a frequent speaker for the Japan External Trade Organization, the Japanese Chamber of Commerce and Industry of Chicago as well as the Indiana Japan Chamber. A leader in the field who is deeply valued for her professional contributions, Mari is often the first Japanese woman serving on various professional boards.
Experience
- Asset Purchase by Japanese manufacturer.
- Barnes & Thornburg obtained not guilty verdicts for clients Tokai Kogyo Ltd. , and its U. S. subsidiary, Green Tokai Co. Ltd. , in a federal criminal jury trial in the U. S. District Court for the Southern District of Ohio in Cincinnati. Tokai and Green Tokai were indicted in June 2016 for allegedly conspiring to fix the prices of automotive body sealing products sold to Honda Motor Co. Ltd in the United States and faced potential fines in the hundreds of millions of dollars.
Credentials
Education
- Indiana University School of Law-Indianapolis, J.D., 1992
- Ochanomizu University - Tokyo, B.A., with honors
- University of Wisconsin-Stevens Point, M.A.
Bar Admissions
- Illinois
Court Admissions
- U.S. District Court for the Northern District of Illinois

