McMahon & Tivnan, PC represents individuals, estates and businesses with federal and state tax issues from audit through collection. It is led by D. Sean McMahon and Ryan Tivnan.The firm defends IRS and state tax matters and excels at resolving difficult and complex tax disputes. We counsel clients through examinations and liability disputes and, when necessary, take disputed issues to court. Collectively, our Boston tax attorneys have more than 100 years of experience investigating and defending IRS and state tax matters.McMahon & Tivnan offer clients unique insights on the real risks presented in disputes with the IRS and planning for complex transactions. They advise clients on the tax considerations of corporate, real estate, partnership, securities and option transactions. The firm also has extensive experience assisting individuals with foreign transaction reporting and penalty disputes, including foreign bank accounts and FBAR requirements, and cryptocurrency transactions.