William J. Kambas


Bill is a partner and the Regional Division Leader of the US private client and tax team.

He focuses on tax planning for multi-national and multi-state personal, active business, and investment activities, with a particular emphasis on tax structuring and choice of business entity for US and non-US business owners and investors.

Bill has represented a wide variety of private and public businesses, including family-owned, start-ups and multi-million dollar enterprises on purely domestic as well as inbound and outbound business transactions, cross-border investments (whether made directly or through investment funds or joint ventures), and qualification for US tax treaty benefits. In particular, he has considerable experience advising non-US persons on the US income and estate tax consequences and tax planning associated with the ownership of US real estate (whether residential or commercial, development, operational, or for personal use).

An integral part of Bill’s work involves assisting families and/or their family offices with the formation, management, and/or periodic evaluation of multinational and/or multi-generational centralized control and management structures, such as family offices and private trust companies.

In addition to numerous speaking engagements, organization memberships and publications, Bill has also been featured as a guest lecturer at the Hellenic Studies Program at Yale University, the Columbia Business School at Columbia University, the University of Connecticut School of Law and the Charles F. Dolan School of Business at Fairfield University.

Secrétaire Mary Marshall





State of Connecticut, 2003

State of New York, 2004

United States Tax Court, 2004

State of Wyoming, 2019

‘Tiered Structures for Family Office Operations: Integrating a Private Trust Company with a Family Office,’ Probate & Property - September/October 2019, co-author

‘Income Taxation of Trusts in the US: Stay Tuned for Controversy,’ Trust Quarterly Review (a STEP publication) - September 2019, co-author

Skidmore College Annual Fund, President

Saint Barbara Greek Orthodox Church Endowment Fund, Chairman

International Fiscal Association (Westchester, NY and Connecticut Region), Executive Committee

‘Cross-Border Case Study,’ STEP Wyoming International Estate Planning Conference - September 21, 2019, co-presenter

‘Avoiding Fiduciary Litigation in the Age of Technological and Digital Transformation,’ Robins Kaplan LLP Wealth Planning, Administration, and Disputes Group, The Future of the Fiduciary - September 12, 2019, panelist

‘Family Forum - Stories from the Front Lines: Dynamic Estates,’ New York State Bar Association, Family Governance Symposium - July 15, 2019, co-presenter



  • English


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