Area of Focus
Washington National Tax

Don Susswein

Area of Focus
Washington National Tax

About Don

Don Susswein leads the partnership tax group in RSM’s Washington National Tax office.  He advises clients and RSM tax professionals in all aspects of the tax treatment of partners and partnerships, as well as areas related to the business or investment activities they engage in, including the taxation of financial instruments and products. 


Don is a tax attorney with decades of high-level experience in all aspects of tax practice including tax litigation and controversy, tax legislation and lobbying, advising clients on the structuring of complex transactions and related securities disclosures, and counseling clients on personal investment and business decisions. He is a frequent commentator on tax policy issues. 

Don’s tax consulting experience, prior to RSM, includes serving as a tax partner in the Washington national tax offices of two large accounting firms and more than a decade as a tax partner in a Wall Street law firm with a market-leading practice in the field of mortgage and asset securitization. Don led that law firm’s work representing several major financial institutions in connection with the development and enactment of significant legislation and regulations affecting the tax treatment of asset securitization and the secondary mortgage market. 

Don’s government experience includes serving as majority tax counsel to the U.S. Senate Committee on Finance during a period when many of the provisions of current law governing partnerships and financial instruments were substantially rewritten. His duties included advising the chairman and members of the Senate Finance Committee on tax issues and negotiating on tax issues with representatives of the Treasury Department, the IRS and the U.S. House of Representatives. 

Before working for the Senate, Don briefed and argued the government’s position in tax controversies before the United States Courts of Appeals, as well as state appellate and high courts as an attorney in the honors program of the Appellate Section of the Tax Division of the Department of Justice. He participated in the review of adverse lower court decisions to determine the government’s position on appeal and prepared submissions to U.S. Supreme Court following appellate court rulings. 

Professional affiliations and designations

  • New York State Bar

  • District of Columbia Bar 


  • Juris Doctor, Yale Law School 

  • Bachelor of Arts, Columbia University 

Area of Focus
Washington National Tax