William J. Kambas

William J. Kambas: Attorney with Withers Bergman LLP
  • Partner at Withers Bergman LLP (416 Attorneys)
  • 157 Church Street, P.O. Box 426, New Haven, CT 06502
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Bill is a partner in the 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, their family offices, and/or family enterprises 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.





‘Essentials of Family Offices for the Estate Planner - A Primer on Functions, Structures, and Related Issues’ at the 53rd Annual Heckerling Institute on Estate Planning by the University of Miami School of Law - January 17, 2019, co-presenter

‘Planning the Estate: Multijurisdictional Estate Planning with a Family Business,’ Columbia University Business School Family Business Management - November 13, 2018, co-presenter

‘Family Office Operations 2018: New Ideas and the Evolving Landscape of Taxation,’ Citi Private Bank - May 3, 2018, co-presenter

‘Tax reform and the family office’, Withers New York and Greenwich event - June 2018, _ speaker

‘5th Annual Family Business School Conference_-_Family Office Panel,’ Columbia Business School - February 9, 2018, moderator

‘US Tax Reform,’ STEP Canada/STEP USA Webcast - January 19, 2018, panelist

‘Interactive round table discussion’, STEP International Estate Planning Conference Wyoming - September 15-16, 2017, moderator

‘Greek Family Firms: Exploring the Logic and Dynamics of the International Shipping Enterprise’ Yale University, The MacMillan Center, Hellenic Studies Program, with Elian Kulukundis, May 2017

‘Encouraging Engaged Ownership through Legal Architecture,’ International Association of Attorneys for Family-Held Enterprises ( AFHE ), Miami, FL, April 27. 2017

‘Direct Asset Investment/Real Estate Investing for Family Offices,’ Peltz International Family Office/Hedge Fund Semiar Series, New York, December 2016.

‘The Impact of Tax Planning on the Flow of Funds within Global Companies,’ in Eurozone Crisis (Economics), Yale University, October 2016

‘Structuring the Global Family Enterprise for Performance and Economic Efficiency,’ STEP Wyoming International Estate Planning Conference 2016, Jackson Hole, WY, October 2016

‘Emergence and Role of Family Offices,’ Expert Webcast Panelist, September 2016.

‘Planning the Estate: International Planning Considerations,’ in Family Business Management, Columbia Business School, New York, August 2016.

‘US Taxation of Resident and Nonresident Aliens’ Surgent Tax Webinar, July 2016.

‘Planning the Estate: Integrating Tax and Estate Planning’ in Family Business Management, Columbia Business School, New York, June 2016.

‘Taxation of U.S. Individuals Working and Living Overseas,’ Surgent Tax Webinar, June 2016.

‘Engaging the Next Gens of the Family Office: Recreating and Preserving Family Wealth,’ Landmark Family Office Forum, New York City, May 2016.

‘Current Developments Regarding the Use of Partnerships in International Transactions,’ International Fiscal Association, Stamford, CT, April 13, 2016.

‘Joining the Family Business,’ Columbia Business School, Family Business Club, New York, March 2016.

‘Alternative Investments for Best Returns: Income Tax Considerations’, Landmark Venture Forum, Greenwich CT - February 2016

‘Maximizing the Bottom Line Return: Tax Considerations for Investments by Family Enterprises’, Landmark Angels & Tech Coast Angels Venture Forum, Newport Coast CA - October 2015

‘Attributes of a Family Enterprise: Utilizing the Asset Holding Structure to Facilitate Business and Operational Succession’, Family Office and Private Wealth Forum, Newport RI - July 2015

‘Family Office 2015 Outlook’, Landmark Venture Forum, Greenwich CT - December 2014

‘Family Office Investing: Tax and Regulatory Considerations’, Landmark Venture Forum, Greenwich CT - September 2014

‘Wealth Transfer Planning’, Charles F. Dolan School of Business, Fairfield University - April 2014

‘The Transfer Pricing Problem’, International Taxation, University of Connecticut School of Law - April 2104

‘Taxation of Gain on a Sale, Exchange or Disposition of a US Partnership Interest by a Non-US Partner’, International Fiscal Association ( IFA ), USA Branch, Westchester County, NY/Connecticut Region (Greenwich, CT) - May 2013

‘Wealth Transfer Planning’, Charles F. Dolan School of Business, Fairfield University - April 2013

‘U.S. Tax Aspects of International Real Estate Financing After Navigating the Fiscal Cliff’, New York City Finance Expo - April 2013

‘US Tax Aspects of International Real Estate Financing’, New York City Finance Expo - March 2012

‘New Frontiers in Estate Planning: Changing Laws and the Modern Family’, The Woman’s Club of Greenwich - January 2012

‘Families, Family Offices and Real Estate’, New York Real Estate Expo - November 2011

‘Moving Across the Pond: Legal Considerations for Expanding to New York’, London to NYC Forum sponsored by New York City Economic Development Corporation - December 2010

‘Foreign Investment in US Real Estate: Challenges and Opportunities’, New York Real Estate Expo - November 2010

‘Themes in Taxation during the Election Season’, Exit Planning Exchange ( XPX Connecticut) and The Association for Corporate Growth ( ACG ) Joint Event, Hartford, Connecticut - October 2010

‘Taxation of US Corporations with Foreign Income’ and ‘Taxation of Foreign Corporations doing business in the US’, National Business Institute ( NBI ), New Haven, Connecticut - June 2007


‘Post-Wayfair State Developments to Watch in 2019,’ Law360 - January 1, 2019, quoted

‘Can You Get an Income Tax Break if You Own Multiple Homes in the US?’ Global - September 20, 2018, quoted

‘Family Offices: Business, Not Personal,’ Wealthmanagement.com - June 11, 2018, quoted

‘S Corporations vs. C Corporations In 2018,’ TaxConnections - May 24, 2018, quoted

‘How 40 ambiguities (and outright errors) in the new tax law could cost you big money,’ Kopitiam Bot - March 14, 2018, quoted

‘How 40 ambiguities (and outright errors) in the new tax law could cost you big money,’ - March 13, 2018, quoted

‘The new alternative minimum tax,’ Withers article - February 13, 2018, co-author

‘Single family office operations 2018: Recent case law and coordination with legislative developments,’ _ Withers article - February 12, 2018, co-author

‘An obscure court case that will have a big affect on family offices,’ Capital - February 8, 2018, quoted

‘How the new federal and New York estate tax exemption could affect your estate plan,’ Withers article - January 2018, co-author

‘How the new federal and Connecticut estate and gift tax exemption could affect your estate plan,’ Withers article - January 2018, co-author

‘Why the US tax reforms are a headache for family offices,’ Family Capital - January 30, 2018, quoted

‘US tax reform - Single family offices and considerations for 2018,’ - January 17, 2018, co-author

‘How the tax code rewrite favors real estate over art,’ The New York Times - January 12, 2018, quoted

‘Tax changes affecting major real estate markets in the USA, ’ Withersworldwide.com - January, 2018, co-author

‘15 tips for year-end planning in light of the GOP tax bill,’ Withersworldwide.com - December 21, 2017, co-author

‘Top federal tax regulations of 2017: Year-in-review,’ Law 360 - December 18, 2017, quoted

‘Effect of proposed US tax bill on family offices and investment vehicles,’ Global Tax Weekly - November 30, 2017, co-author

‘Update: Effect of proposed US House and Senate tax bills on family offices and investment vehicles,’ - November 22, 2017, co-author

‘New Year’s resolutions - Revising partnership agreements as new audit rules take effect January 1, 2018,’ Withersworldwide.com - November 22, 2017, co-author

‘US Inbound Taxation: Senate Finance Committee tax reform plan would overturn recent Tax Court decision,’ Withersworldwide.com - November 10, 2017, co-author

‘Effect of proposed US tax bill on family offices and investment vehicles,’ Withersworldwide.com - November 7, 2017, co-author

‘Art market may lose ‘driving force’ as tax plan targets loophole,’ Bloomberg Quint - November 3, 2017, quoted

‘GOP Aims to Kill the Estate Tax: What it Means for You,’ Fox Business Network - November 3, 2017, quoted

‘Connecticut Legislature passes Budget Bill (Senate Bill 1502)’, Withersworldwide.com - October 30, 2017, co-author

‘Richest Americans doubt they’ll really win in Trump’s tax plan,’ Bloomberg Politics - September 29, 2017, quoted

‘Tax Court holds that non-US persons are not subject to tax on gain from the sale of a US partnership interest which is engaged in a US business under certain circumstances’, Withers article, August 2017, co-author

‘How U.S. Persons Can Be Made Public by the UK Register,’ Estate Planning - August 2017, co-author

‘New York Banking Royalty’s Heirs Are Unloading Art to Save the Family Estate,’ Bloomberg, April 2017, quote

‘A Mediterranean Comparison: Next Steps of FATCA and Global Date Exchange’, Offshore Investment, Issue 260 - October 2015, co-author

‘Aircraft Operations: Tax Tips For Avoiding Turbulence in Private Aircraft Operations’, Estate Planning - August 2015, co-author

‘Like-Kind Exchange Can Help Foreign Investors Reach Goals’, Estate Planning Journal - July 2015, co-author

‘Taxpayers Wynnes: Refund Opportunity for New York City Residents’; June 2015, co-author

‘Assessing US Tax Consequences of a Departure from the Euro’, Lexis Federal Tax Journal - March 2015, co-author

‘When in Rome...Pointers for US, UK, and Russian Buyers of Italian Property’, STEP Journal - November 2014, co-author

‘The Complete Family Office Handbook: A Guide for Affluent Families and the Advisors Who Serve Them’ - January 2014, co-author

‘Structure and Integration: The Architecture of Succession’, Family Firm Institute, FFI Practitioner - August 2013

‘Global Mobility: U.S. tax considerations associated with obtaining a green card’, Trusts & Estates - August 2012

‘Cross-Border Business Should Benefit From Malta’s User Friendly Tax System and US-Malta Income Tax Treaty’, LexisNexis Tax Law Legal Newsroom and Withers Bergman LLP Briefing Notes - August 2011

‘Ideas for Greece: International Entrepreneurship for Economic Growth’, Odyssey Magazine - 2010 Year-End Issue, contributor

‘Small Business Jobs Act of 2010’, LexisNexis Tax Law Legal Newsroom and Withers Bergman LLP Briefing Notes - October 2010

‘Cross Border Philanthropy: Why is Doing the Right Thing Never Easy?’, STEP U.S.A. Issue 10 - November 2009

‘Update on the 2009 U.S.-France Protocol: Potential Significant Changes in the U.S.-France Income Tax Treaty’, LexisNexis Tax Law Legal Newsroom and Withers Bergman LLP Briefing Notes - October 2009

‘Giving to Greece: The Challenge of Cross-Border Philanthropy’, Odyssey - May/June 2009.

‘Corporate Income Tax Nexus What Constitutes Doing Business in Connecticut?’, Lexis CT Tax P.I. 2,978 - 2007

‘Tax Consequences of Post-Merger Net Operating Losses’, Lexis CT Tax P.I. 2,385 (2007)

‘Taxation of Income from the Cancellation of Debt’, Lexis CT Tax P.I. 2,384 (2007)

‘Connecticut Restrictions on the Deductibility of Interest Expenses’, Lexis CT Tax P.I. 2,383 (2007)

‘Connecticut Dividends Received Deduction’, Lexis CT Tax P.I. 2,845 (2007)

‘Connecticut Restrictions on the Deductibility of Royalty and Intangible Expenses’, Lexis CT Tax P.I. 2,382 (2007)

‘Tax Credit for Financial Institutions’, Lexis CT Tax P.I. 2,846 (2007)

‘Tax Reform and Modernization’, 108 Tax Notes 1447 (2005)

‘Uncle Sam Sneaks a Peak Data Mining in Tax Compliance’, 26 Nat’l. L. J. 42 (2004)

‘The Development of the U.S. Banking System From Colonial Convenience to National Necessity’, 28 RUTGERS L. REC . 4 (2004)

‘The EU Safe Harbor Principles Offer Comprehensive Privacy Protection’, 9 ILSA J. Int’l. & Comp. L. 149 (2003)

‘Protecting Debtor’s Subsidiaries Extending the Automatic Stay of 11 U.S.C. 362 To Foreign Subsidiaries’, 17 Conn. J. Int’l. Law 127 (2002)


Areas of Practice (9)

  • Families and family offices
  • Private companies
  • Public companies
  • Europe
  • Greece
  • Owners and entrepreneurs
  • Family businesses
  • Luxury assets
  • Professional advisers

Education & Credentials

Contact Information:
203-361-9194  Phone
203 974 0313  Phone
203 285 1613  Fax
University Attended:
Skidmore College, B.A., 1996; University of Connecticut School of Business, M.B.A., 2003
Law School Attended:
University of Connecticut School of Law, J.D., 2003; University of Connecticut School of Law, Certificate in Tax, 2003
Year of First Admission:
2003, State of Connecticut; 2004, State of New York; 2004, United States Tax Court


Skidmore College Annual Fund, President

Saint Barbara Greek Orthodox Church Endowment Fund, Chairman

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

Hellenic-American Chamber of Commerce

Hellenic Bar Association of Connecticut

New York State Bar Association

Connecticut Bar Association

American Bar Association


Peer Reviews

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*Peer Reviews provided before April 15, 2008 are not displayed.

Documents (9)

Documents by this lawyer on Martindale.com

New Haven, Connecticut

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