Jay focuses his practice on business and transactional tax law. He advises a wide variety of corporations and high-net-worth individuals on tax and legal aspects of business and real estate activities and represents these taxpayers before federal and state taxing authorities. He also works with high-net-worth individuals and business owners to organize their personal income tax and estate planning affairs in order to maximize wealth preservation and minimize tax on transfers to family members, charities and other recipients. This is accomplished through the use of the latest sophisticated estate planning strategies, including family limited partnerships, installment sales to defective grantor trusts, the formation of family charitable foundations, and other similar techniques.

Jay was one of the early proponents of Opportunity Zones, and has been at the leading edge of the legislation and related tax incentives since they were first enacted in the Tax Cuts and Jobs Act in late 2017. He has spoken at over 25 regional and national conferences on the structuring of Qualified Opportunity Funds and Qualified Opportunity Zone businesses, and has helped form more than 50 successful Qualified Opportunity Funds thus far, ranging in size from small private transactions to transactions in the $200 million to $500 million range.

Jay has represented and advised numerous public and private companies, as well as private equity and venture capital firms, on investment and acquisition transactions and on the disposition of business interests, in transactions ranging from early-stage investments in high-tech startups to acquisitions and sales of mature, late-stage companies and publicly traded corporations.

Another focus in Jay's practice is the taxation of intellectual property, including tax aspects related to the development, licensing and exploitation of intellectual property rights, the migration of valuable intellectual property to offshore jurisdictions and the tax-efficient sale of intellectual property rights.

Jay is the author of Practical Guide to Mergers, Acquisitions and Business Sales, Second Edition, a textbook published by National Underwriter Company, an ALM (American Legal Media) Business. He has extensive experience in the areas of structuring mergers, acquisitions, business sales, and related business transactions. He teaches graduate-level courses on the buying and selling of businesses at Boston University School of Law in the Graduate Tax Program and at Bentley University McCallum Graduate School of Business in the Masters of Taxation Program.

Jay has been the recipient of numerous journalism and writing awards, and has authored two books and more than 1,000 articles published in such diverse publications as The Tax Lawyer, Worth Magazine, Venture Capital Magazine, Banker & Tradesman, Mass High Tech, Hemispheres Magazine, Contract Professional, Trusts & Estates Magazine, The Boston Globe, The Boston Herald, The Boston Business Journal and The Boston Phoenix. Mr. Darby is a frequent contributor to the World Trade Executive family of publications, including Practical International Tax Strategies, Practical European Tax Strategies, and Practical US Tax Strategies, and is a member of the editorial and advisory board of World Trade Executive.

Jay served as a member of the Board of Assessors for the Town of Watertown from 1993-2011, and has served as pro bono legal and tax counsel to a variety of Boston-area charitable organizations. He is a former president of the Boston Police Foundation (2008-2012) and is currently president of the Watertown Police Foundation, an organization he founded in April 2013 to help Watertown recover from the violent events that led to the capture of the Marathon bombing suspects.  

Bar & Court Admissions

  • Massachusetts
  • U.S. Tax Court


  • J.D., cum laude, Harvard Law School
  • B.S., magna cum laude, with Department of Honors in Mathematics, University of Illinois at Urbana-Champaign

Community Engagement

  • Writer's Council, Opportunity Zone Magazine (2019)
  • Founder and President, Watertown Police Foundation (2013 to present)
  • Former President and Member of the Board of Trustees, Boston Police Foundation (2008-2012)
  • Member, Board of Assessors, Watertown, Massachusetts (1993-2011)
  • Adjunct Professor, Boston University School of Law, Graduate Tax Program (2003 to present)
  • Adjunct Professor, Masters in Taxation Program, Bentley University (2007 to present) 
  • Member of the Advisory Board of World Trade Executive for the following publications:
    • Practical US/International Tax Strategies
    • Practical European Tax Strategies
    • Practical US/Domestic Tax Strategies
  • Boston Bar Association

Awards & Honors

  • Best Lawyers in America® (2010-2016, 2018-2021)
  • Legal 500 U.S. (2014, 2015, 2019-2020)
  • Top 25 Opportunity Zone Influencer, OZ Magazine (2019)
  • Tax Writer of the Year - 2007 and 2011, World Trade Executive, Inc., a division of Thomson Reuters
  • New England Press Association, First Place for Sports Column writing (1990)
  • Special Recognition Award from the Armenian Museum and Library of America (1988)
  • AV Preeminent®, Martindale-Hubbell® Peer Review Ratings™

Seminars & Presentations


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