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Sean Langan – Associate

Overview

Sean Langan is a tax lawyer representing individuals and businesses engaged in tax controversies with the Internal Revenue Service (“IRS”) and Massachusetts Department of Revenue (“DOR”). Sean is a graduate of Loyola University Chicago School of Law, where he graduated magna cum laude and served as research assistant to the Dean.

Sean joined McMahon Tivnan after six years as an attorney at the IRS. Sean’s experience with the IRS allows him to offer clients firsthand knowledge of the organization, often proving useful in resolving tax disputes.

Experience

Sean’s tax practice includes:

  • Collections matters, including installment agreements, offers in compromise, and innocent spouse relief
  • Appeals, including administrative appeals through the IRS Office of Appeals and Massachusetts DOR
  • Voluntary Disclosure, including helping to bring taxpayers who have not filed returns in several years into compliance
  • Foreign Bank Accounts and FBAR Requirements, including representing taxpayers with unreported foreign bank accounts and delinquent FBAR returns, and helping them navigate voluntary disclosure programs

Previous Experience

IRS: Office of Professional Responsibility
  • Advised Director, OPR on appropriate disposition of tax practitioner disciplinary matters
  • Negotiated disciplinary agreements with practitioners and their representatives, preparing settlements with appropriate terms and conditions for reinstatement
  • Delivered Spanish-language presentations to audiences of several hundred practitioners at Nationwide Tax Forums (NTF), answering participant questions in Spanish
IRS: Exempt Organizations
  • Provided technical consultations to IRS agents examining charities and nonprofits
  • Developed and delivered over twenty continuing professional education “CPE” programs covering nonprofit tax law topics
  • Co-authored over ten IRS Technical Guides offering guidance to practitioners and public on areas of nonprofit tax law

Honors & Awards

  • IRS Excellence Award (2022, 2023, 2024)
  • Presidential Management Fellow (2019-2021)
  • CALI Awards: Administrative Law and Advocacy (top performer in class)