Marc Grossberg's primary practice is representing clients in tax controversies at the examination, Internal Revenue Service appeal and trial and federal appeals levels, collection issues and pre-IRS examination compliance issues, including filing and foreign accounts and unique issues. Recent representations include bringing taxpayers "in from the cold," meaning assisting them in becoming compliant with the Internal Revenue Service before the Internal Revenue Service has discovered the non-compliance, both as part of the IRS offshore voluntary compliance initiatives and otherwise. In handling a variety of federal tax controversies, he has represented a number of taxpayers in controversies with the IRS involving contributions to and participation in employee benefit plans, has represented plan sponsors in controversies with the IRS involving sponsored plans and represented persons and entities who participated in or were employee-sponsors of plans in claims against plan sponsors for the plans not having the tax benefits representatives.His practice also includes negotiating, restructuring and planning the tax consequences of large and complex loan workouts, obtaining exempt organization determinations, requesting and obtaining private letter rulings from the IRS, representing clients in business litigation, including, without limitation trials in state and federal district court between contracting parties and between shareholders of public companies, structuring, negotiating and documenting complex transactions such as acquisitions, partnerships and joint ventures, financings and syndications. Recent non-tax litigation and controversy work includes representing persons who have claims against tax-shelter promoters, federal civil forfeiture proceedings, Sarbanes-Oxley whistleblower case and wrongful denial of long-term disability income benefits. Has lectured numerous times at tax programs including those sponsored by NYU, the Southern Federal Tax Institute, the Tax Section of the American Bar Association, the American Law Institute and BNA/CITE.