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Mark S. Klein

Partner, Chairman of the Firm
  • New York
  • Florida
  • U.S. Supreme Court

State University College at Buffalo, B.S., Summa Cum Laude

University at Buffalo School of Law, J.D., Magna Cum Laude

Mark is Chairman of the Firm and concentrates his practice in New York State and New York City tax matters. He has more than 35 years of experience with federal, multistate, state and local taxation -- and may be best known for his public speaking on tax topics. Mark splits his time between the Firm's New York City and Buffalo offices.

Mark has represented numerous Fortune 500 companies in connection with corporate, withholding and sales tax audits as well as dozens of individuals who appear on the Forbes 500 list of wealthiest individuals in the United States in connection with New York income tax inquiries.

Mark taught courses in the Tax Certificate Program in the School of Management at the University of Buffalo on state taxation and tax practice and procedure. He is a member of The CPA Journal editorial review board and has written numerous books, articles and treatises on the subject of multistate taxation. Mark is the general editor of LexisNexis Tax Practice Insights: New York; the editor of New York Tax Highlights and the contributing editor of CCH's Annual Guidebook to New York Taxes. He is the co-author of the ABA Sales & Use Tax Desk Book, CCH's New York Residency and Allocation Audit Handbook; New York Sales and Use Tax Answer Book, the New York State Bar Association's Contesting New York State Tax Assessments, 4th Edition; and RIA's New York Tax Handbook and New York City Tax Handbook. Mark is also a contributor to numerous professional and industry-focused publications.

Honors

  • Listed, Best Lawyers in America (Tax Law, Litigation and Controversy -Tax) 2018, 2019
  • Listed, Upstate New York Super Lawyers, 2007 - 2018
  • Who's Who in American Law

  • Martindale-Hubbell, 1998-2018 – highest possible peer review rating in legal ability & ethical standards for twenty years

News

Presentations

  • 2019 Summer Tax Series
    Understanding New York State Tax Issues of 2019
    The Harvard Club 35 W. 44th Street, New York, NY, June 12 - August 7, 2019
  • CPA Academy: Nexus Issues for Businesses
    May 2, 2019
  • 2019 Florida Residency Seminar Series
    Boca Raton, Fort Lauderdale, Naples, Manalapan, Sarasota, Florida, January and February 2019
  • CPA Academy - Nexus Issues for Businesses
    January 24, 2019
  • CPA Academy - Nexus Issues for Businesses
    December 19, 2018
  • New Jersey CPA Club
    Mayfair Farms, 481 Eagle Rock Ave., West Orange, NJ 07052, December 13, 2018
  • Accountants Continuing Education (ACE)
    New Yorker Hotel, 34th Street & 8th Avenue, New York, NY 10001, December 12, 2018
  • CPA Club of Bergen County
    Saddle Brook Marriott, 138 New Pehle Ave., Saddle Brook, NJ 07663, December 5, 2018
  • 2018 State and Local Tax Update NYS + NYC Accountants Continuing Education (ACE), NY Tax Update
    Uniondale, New York, November 29, 2018
  • 2018 Long Island Tax Symposium by National Conference of CPA Practitioners, NY Tax Update
    Woodbury, New York, November 14-15
  • 65th Tax Institute, UB School of Management, NY State Tax Update
    Buffalo, New York, November 9, 2018
  • New York State Society of CPAs (NYSSCPAs), Wayfair Decision- What Does it Mean?
    New York, New York, November 7, 2018
  • CPA Academy, Nexus Issues for Businesses
    November 30, 2018
  • Nexus Issues for Businesses
    October 9, 2018
  • Changing Your Residency and the State's Response to Tax Cuts and Jobs Acts
    New York, New York, October 9, 2018
  • Tri-State Business Tax Update: Reviewing SALT developments in the business tax arena in New York, New Jersey, and Connecticut
    September 25, 2018
  • Accountants Continuing Education– Mid-Year Tax Conference – NYS Tax Update
    New York, New York, August 22, 2018
  • 2018 Summer Tax Series
    Understanding New York State Tax Issues of 2018
    The Harvard Club 35 W. 44th Street, New York, NY, June 13 to August 1, 2018
  • AICPA Engage 2018
    MGM Grand, Las Vegas, NV, June 9-14, 2018
  • Florida Residency Seminar Series 2018
    Palm Beach, Boca Raton and Naples, Florida, January, February & March 2018
  • NYSSCPAs- Sid Kess Workshop
    January 31, 2018
  • CPA Club or Bergen County, Abandoned Property
    Saddle Brook, New Jersey, January 18, 2018
  • CPA Club of Bergen County- NY Tax Update
    January 18, 2018
  • CPA Club of NJ- NY Tax Update
    January 17, 2018
  • CPA Club of New Jersey, NY Tax Update
    West Orange, New Jersey, January 17, 2018
  • Accountants' Continuing Education Presentation
    New York, New York, January 4, 2018
  • Accountants Continuing Education (ACE) NY Tax Update
    December 14, 2017
  • Doing Business on the Web - Multistate Tax Implications Webcast
    November 29, 2017
  • New York Tax Update
    November 17, 2017
  • 15th Annual Long Island Tax Professionals Symposium
    November 15, 2017
  • 2017 Summer Tax Series
    Understanding New York State Tax Issues of 2017
    The Harvard Club 35 W. 44th Street New York, NY, June 7 to August 2, 2017
  • ACE: NY Tax Update
    New Yorker Hotel, New York, November 10, 2016
  • Foreign Asset Reporting and Prosecutions
    The Harvard Club, 35 West 44th Street, New York, NY 10036, November 2, 2016
  • State Withholding Obligations
    Hodgson Russ LLP, 1540 Broadway, 24th Floor, New York, NY 10036, October 27, 2016
  • Multi-State and Sales Tax
    New York, NY, October 26, 2016
  • Residency Overview
    New York, NY, August 24, 2016
  • Handling an Audit Soup to Nuts
    New York, NY, August 17, 2016
  • AICPA Tax Strategies Conference: Residency and Domicile Planning
    Las Vegas, NV, May 25, 2016
  • AICPA Tax Strategies Conference: Nexus and Apportionment
    Las Vegas, NV, May 24, 2016
  • Foundation of Accounting Education Webcast: Corporate
    Wall Street, NYC, February 9, 2016
  • NYSSCPA Tri-State Conference: New York Tax Update
    January 21, 2016
  • Florida Residency Seminar Series 2016
    Boca Raton, Naples, & Palm Beach Florida, January & February 2016
  • CPA Club New York Tax Update
    New Jersey, January 7, 2016
  • ACE: New York Tax Update
    Long Island, NY, December 16, 2015
  • Foundation of Accounting Education- Suffolk Chapter: New York Tax Update
    Melville, NY, December 12, 2015
  • NCCPAP Annual Tax Plenary Conference: New York Tax Update
    Baruch College, NY, December 8, 2015
  • NCCPAP Tri-State: New York Tax Update
    Tarrytown, NY, December 8, 2015
  • NJSCPA Multistate: New York Tax Update
    New Jersey, December 3, 2015
  • New Jersey Education Association Conference: New York Tax Update
    New Jersey, December 2, 2015
  • NYSSCPA West Chapter: New York Tax Update
    Rye Brook, NY, December 1, 2015
  • Long Island Tax Professionals Symposium: New York Tax Update
    Woodbury, NY, November 18, 2015
  • NYSSCPA NYS Taxation Conference: New York Tax Update
    New York Bar Association, NYC, November 10, 2015
  • AICPA National Tax Conference: Audit Analytics
    Washington, DC, November 2, 2015
  • UB Tax Institute: New York Tax Update
    Buffalo, NY, October 30, 2015
  • ACE: New York Tax Update
    New York, NY, October 28, 2015
  • NYSSCPA Construction Conference: Sales Tax and Residency
    Wall Street, NYC, October 21, 2015
  • Estate Analysts of WNY: New York Tax Update
    Buffalo, NY, October 5, 2015
  • 46th Annual Sid Kess Conference: New York Tax Update
    New York, NY, September 10, 2015
  • Hodgson Russ Summer Tax Series: Covering the Most Important State Tax Issues in 2015 
    The Harvard Club, 35 W. 44th Street, New York, NY, Summer 2015
  • Foundation of Accounting Education Webcast: Residency
    Wall Street, NYC, July 23, 2015
  • 2015 Tax Roadshow
    Summer 2015
  • AICPA: Multistate Rebroadcast
    New York, NY, June 26, 2015
  • Tax Roadshow: New York State Update
    Long Island, NY, June 17, 2015
  • AICPA: Residency Rebroadcast
    New York, NY, June 16, 2015
  • ISA Boston: New York State Update
    Boston, MA, June 12, 2015
  • Contesting Tax Assessment
    Harvard Club, NYC, June 10, 2015
  • Foundation of Accounting Education Webcast: Multistate
    Wall Street, NYC, June 8, 2015
  • Leib Preis: New York Tax Update
    New Jersey, June 2, 2015
  • Florida Residency mini session
    Boca Raton, FL, February 26, 2015
  • Florida Residency 2015
    Florida, February 2015
  • Foundation of Accounting Education Webcast: Residency
    Wall Street, NYC, February 4, 2015
  • CPA Club: New York Tax Update
    New Jersey, January 14, 2015
  • NCCPAP 2014 Tri-State Seminar: New York Tax Update
    Tarrytown, NY, December 16, 2014
  • ACE: New York Tax Update
    New York, NY, December 15, 2014
  • Foundation of Accounting Education- Suffolk Chapter: New York Tax Update
    Long Island, NY, December 13, 2014
  • ACE: New York Tax Update
    Long Island, NY, December 4, 2014
  • NJSCPA: New York Tax Update
    East Hanover, NJ, November 21, 2014
  • NCCPAP: New York Tax Update
    Woodbury, NY, November 19, 2014
  • Foundation for Accounting Education Annual Westchester Tax Conference: New York Tax Update
    Armonk, NY, November 10, 2014
  • UB Tax Institute: New York Tax Update
    Buffalo, NY, November 7, 2014
  • Foundation for Accounting Education Hospitality Conference: New York State Update
    New York, NY, November 4, 2013
  • AICPA: Residency and Sales Tax
    Washington, DC, November 3, 2014
  • Foundation of Accounting Education Construction Conference: Sales Tax
    New York, NY, October 22, 2014
  • Foundation for Accounting Education Webinar: How to Handle an Audit
    New York, NY, October 21, 2014
  • Foundation for Accounting Education Webcast: How To Handle An Audit
    Wall Street, NYC, October 21, 2014
  • Bonadio Group: New York Tax Update
    Pittsford, NY, October 17, 2014
  • Legislative Changes and Residency Update
    UJA Federation, NYC, September 18, 2014
  • Foundation for Accounting Education: New York Tax Update
    New York, NY, July 16, 2014
  • Foundation for Accounting Education: New York Tax Update
    New York, NY, July 9, 2014
  • Foundation of Accounting Education Webcast: Sales Tax
    New York, NY, June 18, 2014
  • 2014 Tax Series Roadshow
    June & July 2014
  • Smart Pros: Residency
    New York, NY, June 5, 2014
  • Leib Preis Study Group: New York Tax Update
    New Jersey, June 4, 2014
  • Philanthropic Planning Group: Changing Your Domicile
    NYU Kimmel Center, NYC, May 21, 2014
  • New York State Bar Association: Sales Tax Developments
    NYC- Cornell Club, April 29, 2014
  • Foundation of Accounting Education Webcast
    Wall Street, NYC, January 29, 2014
  • Florida Residency Seminar Series 2014
    Palm Beach & Naples, FL, January & February 2014
  • Doing Business on the Web: Taxes, Security Breaches & Cyber Troubles
    New York, NY, January 23, 2014
  • CPA Club of Bergen County: NY Update
    New Jersey, January 22, 2014
  • National Conference of CPA Practitioners: New York Update
    Tarrytown, NY, December 17, 2013
  • Foundation for Accounting Education Westchester Chapter Conference: New York Update
    Armonk, NY, December 13, 2013
  • ACE: New York Update
    Uniondale, NY, December 12, 2013
  • Foundation for Accounting Education NYS Annual Tax Conference: Sale of a Business
    New York, NY, December 10, 2013
  • New York State Society of CPAs Nassau Chapter Conference
    Uniondale, NY, December 7, 2013
  • American Institute of CPAs webcast: New York Update
    New York, NY, December 6, 2013
  • Long Island Symposium: New York Update
    Wppdbury, NY, Novemeber 20 & 21, 2013
  • ACE: New York Update
    New York, NY, November 12, 2013
  • Buffalo Tax Institute: New York Update
    Buffalo, NY, November 7, 2013
  • American Institute of CPAs National Tax Conference: Tax traps of Doing Business on the Web
    Washington, DC, November 5, 2013
  • American Institute of CPAs National Tax Conference: Nuts and Bolts of Changing your Residence
    Washington, DC, November 5, 2013
  • Foundation for Accounting Education Tax Plenary Conference: NYS Income Tax
    New York, NY, October 30, 2013
  • Foundation for Accounting Education Entertainment & Sports Committee: Personal Income Tax
    New York, NY, October 29, 2013
  • Bonadio Group: New York Update
    Rochester, NY, October 25, 2013
  • United Jewish Appeal Federation: New York Update
    New York, NY, October 9, 2013
  • Foundation for Accounting Education Construction Conference: New York Update
    New York, NY, August 8, 2013
  • Foundation for Accoutning Education CFO Conference: New York Update
    New York, NY, July 17, 2013
  • 2013 New York Summer Seminar Series Roadshow
    June & July 2013
  • Leib Preis Tax Study Group: New York Update
    New Jersey, June 11, 2013
  • Estate Planning Council of Westchester County: Tax Update With Emphasis on Domicile
    White Plains, NY, June 5, 2013
  • American Assocation of Attorney- Certified Public Accountants: Hot Topics in New York Tax Enforcement
    New York, NY, June 4, 2013
  • The Ayco Company: Multistate Update
    Boston, MA, June 3, 2013
  • American Institute of CPAs: Multistate Tax (Individual & Business)
    Las Vegas, NV, May 21, 2013
  • American Institute of CPAs: Best Tax Ideas Panel
    Las Vegas, NV, May 20, 2013
  • New York State Bar Association 17th Annual NYS & NYC Tax Institute: New York State Update
    New York, NY, May 7, 2013
  • The CPA Club: New York State/ New York City Update
    West Orange, NJ, February 6, 2013
  • Know the Angles to Resolving U.S. Tax Disputes
    Toronto, ON, January 31, 2013
  • ISA Meeting: New York Update
    Phoenix, AZ, January 24 & 25, 2013
  • Florida Residency Seminar Series 2013
    Palm Beach & Naples, FL, January & February 2013
  • Know the Angles to Resolving U.S. Tax Disputes
    New York, NY, January 16, 2013
  • PrimeGlobal: Nonresident Income Tax
    San Diego, CA, January 7, 2013
  • 2012 New York Summer Seminar Series
    June & July 2012
  • New Jersey Summer Tax Seminar
    Morristown, NJ, June 5, 2012
  • Florida Residency Seminar Series 2012
    Palm Beach & Naples, FL, January & February 2012
  • Changing Your Residence
    Buffalo, NY, July 19, 2011
  • 2011 New York Summer Seminar Series
    June & July 2011
  • Florida Residency Seminar Series 2011
    Palm Beach & Naples, FL, January & February 2011
  • Changing Your Residence
    Buffalo, NY, July 22, 2010
  • 2010 New York Summer Seminar Series
    June & July 2010
  • Avoiding and Responding to New York Criminal Tax Audits and Investigations
    Uniondale, NY, January 27, 2010
  • Standing Tall Against Aggressive Taxing Agencies 2009-2010
    New York, NY, October 27, 2009
  • Changing Your Residence
    July 16, 2009
  • 2009 New York Summer Seminar Series
    June & July 2009
  • Avoiding and Responding to New York Criminal Tax Audits and Investigations
    New York, NY, January 28, 2008

Publications

Professional Associations

  • New York State Tax Appeals Tribunal Advisory Committee
  • Executive Committee of ACE Accounting Society
  • Editorial review board, New York State Society of CPAs' CPA Journal
  • Former chair, Bar Association of Erie County Cooperation with the Accounting Profession Committee
  • American Bar Association Tax Committee
  • New York State Bar Association Tax Committee
  • Former chair, Bar Association of Erie County Tax Committee