Simpson Thacher & Bartlett LLP

Environmental

Co-Head of the Firm’s Environmental Practice, Toby Chun has served as lead environmental counsel for many of his clients’ most environmentally challenging transactions. Toby’s practice focuses on managing the environmental aspects of a wide variety of corporate transactions, including mergers and acquisitions, capital markets offerings, acquisition financing, and real estate transactions. Drawing upon his experience working on numerous transactions spanning a diverse range of businesses and industries in the United States and around the world, Toby helps his clients achieve their business objectives by evaluating the environmental risks and liabilities associated with target companies and properties, working with environmental consultants to assess and appropriately contextualize known and potential liabilities, negotiating transaction documents on environmental terms consistent with his client’s goals, helping to optimize environmental insurance coverage, managing the resolution of environmental issues, and keeping abreast of the latest developments for emerging contaminants and other environmental topics.

Rated AV Preeminent in Martindale-Hubbell; Ranked in Band 1 for Environment: Mainly Transactional (DC) by Chambers USA 2025.

National Asian Pacific American Bar Association; APABA-DC.

University of Chicago Law School, J.D., 1996; Stanford University, M.S., Environmental Engineering and Science, 1993; Stanford University, B.S., Biological Sciences, 1992.

Teaching Experience: Lecturer, University of Chicago Law School, Environmental Transactions and Bankruptcy, 2021-2023, 2025.