Tamar Rosenberg is a partner in the Tax, Employee Benefits, and Trust & Estates Practice Group in the firm's New York office. She is a Leader of the firm’s Nonprofit Sector Team.

Areas of Practice

Tamar specializes in corporate, tax exemption and other laws specific to nonprofits and philanthropy.  She leverages her technical expertise and diverse practical experience across sectors to help large nonprofit organizations – and those funding or doing business with them – to achieve their strategic goals, comply with the complex laws regulating nonprofits and protect their interests.

Tamar has been individually recognized by Legal 500 as both a Recommended Lawyer – Tax: Not-for-profit and a “Next Generation Lawyer” (2019-2022), as well as a “Best Lawyer in America,” by Best Lawyers, 2023. 



  • Supporting numerous charitable and for-profit employers in providing relief relating to the COVID-19 pandemic to employees, their families and the public.
  • Advising a large public healthcare industry company on options to conduct philanthropic activities, including grantmaking and direct charitable programs, and forming a company foundation and providing extensive guidance on legal compliance, including considerations relating to charitable and community-focused activities conducted directly by the for-profit company. 
  • Advising multiple family foundations on a corporate governance matters, including a compliance review and overhaul.
  • Advising family foundations and public charities on international grantmaking issues.
  • Leading Sheppard Mullin’s pro bono effort involving a team of Sheppard Mullin attorneys from across practice groups and specialty areas to provide legal support to a volunteer project to produce and distribute face shields to front line healthcare workers fighting COVID-19 in Los Angeles.
  • Assisting clients with obtaining federal, state, and local income tax-exemption and with charitable solicitation registration
  • Advising clients on structuring and implementing complex affiliations and joint ventures between tax-exempt and for-profit organizations
  • Counseling organizations on a wide range of issues relating to maintaining qualification for tax-exempt and public charity status and compliance with state not-for-profit corporation laws, including: corporate governance, private inurement and private benefit; excess benefit transactions; unrelated business income tax; lobbying limitations; private foundation excise taxes; grant-making, scholarships, and awards; foreign charitable activities; fundraising; charitable giving; supporting organizations; donor-advised funds; endowment funds and restricted gifts; and executive compensation
  • Advising clients on federal, state, and local tax reporting issues impacting not-for-profit organizations, including Forms 990, 990-PF, and 990-T and foreign reporting forms
  • Assisting organizations with various tax issues common to tax-exempt organizations, including real property tax exemptions, sales and use tax and compensation and benefits issues
  • Advising not-for-profit clients on corporate restructurings, mergers, acquisitions, reorganizations, dissolutions, and conversions of not-for-profit organizations to for-profit status



Bob Gerber Pro Bono Award, Sheppard Mullin, 2022

Best Lawyer in America, Best Lawyers, 2023-2024

Next Generation Lawyer, Legal 500, 2019-2023

Recommended Lawyer - Tax: Not-for-profit, Legal 500, 2019-2022

  • Legal500 US Next Generation



  • Metropolitan Corporate Counsel, 12.2015
  • Is a Hybrid Just What the Doctor Ordered? Evaluating the Potential Use of Alternative Company Structures by Healthcare Enterprises
    ABA: The Health Lawyer, 04.30.2013
  • Are Hybrids Really More Efficient? A "Drive-By" Analysis of Alternative Company Structures
    ABA: Business Law Today, 09.21.2012
  • New York Takes Bold Action in Joining the Intensifying Focus on Not-for-Profit Compensation
    The Exempt Organization Tax Review, 11.10.2011
  • Section 501(h) Elections and the Affiliated Group Rules
    Taxation of Exempts, 05.2010
  • A Creative Twist on the Joint Venture
    The Exempt Organization Tax Review, 02.2006

Labor and Employment Law Blog Posts

Healthcare Law Blog Posts

Media Mentions

Speaking Engagements

  • “Nonprofit News and Tax Exempt Challenges”, Institute for Nonprofit News, webinar, January 30, 2019.



J.D., New York University School of Law, 2003

B.A., University of Pennsylvania, 2000, magna cum laude


  • New York
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