Sean McMahon
Lecturer
LLM, Boston University School of Law
JD, New England School of Law
BA, Fairfield University
Biography
D. Sean McMahon is a former Senior Attorney with the IRS Office of Chief Counsel and a former Special Assistant United States Attorney for Massachusetts and New Hampshire where he was responsible for tax cases. Sean has more than fifteen years of experience investigating and defending IRS and state tax matters and excels at resolving difficult and complex tax disputes. He counsels clients through examinations and liability disputes and, when necessary, takes disputed issues to court. Sean has been named to the Massachusetts Super Lawyers list in the area of tax law.
As a former IRS attorney, Sean offers clients unique insights on the real risks presented in disputes with the IRS and planning for complex transactions. He advises clients on the tax considerations of corporate, real estate, partnership, securities and option transactions. Sean also has extensive experience assisting individuals with foreign transaction reporting and penalty disputes, including foreign bank accounts and FBAR requirements.
- Profile Types
- Faculty, Graduate Tax LLM, Lecturers & Adjunct Professors, and Part-Time Faculty
- Areas of Interest
- Tax Law
Activities & Engagements
No upcoming activities or engagements.
Courses
TAX PRACTICE & PROCEDURE: LAW TX 907
Structure of the U.S. tax system; administration of the Internal Revenue Code by the Internal Revenue Service; ethics of tax practice and the regulation of tax practitioners; study of the administrative processing of tax returns; handling of audits, statutes of limitations, assessment of deficiencies and penalties, claims for refund, hearings before the Appeals Office, closing agreement, tax liens, tax collection procedures and civil and criminal aspects of tax fraud. Introduction to aspects of litigation in the Federal District Court, U.S. Court of Federal Claims, and U.S. Tax Court.
FALL 2025: LAW TX 907 A1 , Sep 2nd to Dec 19th 2025| Days | Start | End | Credits | Instructors | Bldg | Room |
|---|---|---|---|---|---|---|
| Thu | 4:20 pm | 6:20 pm | 2 | Sean McMahonEvan Taras |
| Days | Start | End | Credits | Instructors | Bldg | Room |
|---|---|---|---|---|---|---|
| ARR | 12:00 am | 12:00 am | 2 | Sean McMahonEvan Taras |
| Days | Start | End | Credits | Instructors | Bldg | Room |
|---|---|---|---|---|---|---|
| Thu | 4:20 pm | 6:20 pm | 2 | Mark J. DeFrancisco |
| Days | Start | End | Credits | Instructors | Bldg | Room |
|---|---|---|---|---|---|---|
| ARR | 12:00 am | 12:00 am | 2 | Mark J. DeFrancisco |