Related People
Mayer Brown, a leading global law firm, announced today that Shawn R. O’Brien has joined the firm’s Tax Controversy practice in the Houston office. Previously, Mr. O’Brien managed the Tax Controversy Practice Group at Jackson Walker LLP, where he was a partner in Houston.

“Shawn has a proven track record of handling complex, cutting-edge tax disputes, and he represents clients on various significant tax issues before the IRS as an advocate in trial and appellate litigation,” said partner Joel Williamson, co-leader of Mayer Brown’s Tax Controversy practice. “His experience with a wide range of tax controversy issues and tax transactions, particularly within the energy industry, further expands the reach of Mayer Brown’s prominent Tax Controversy and Transfer Pricing practices to Texas, one of the most important markets in the United States.”

Referencing the firm’s global platform, Mr. O’Brien said, “As tax laws rapidly evolve, Mayer Brown’s geographic scope and exceptional Tax practice capabilities will enable me to offer multinational companies a superior level of experience with cross-border tax issues. I look forward to applying my deep knowledge and experience to solve tax disputes and transactional tax issues for clients facing aggressive enforcement by worldwide taxing authorities.”

Mr. O’Brien represents clients in all types of civil and criminal tax controversies and in every kind of dispute resolution with taxing authorities on the state and federal levels. He routinely advises clients on various tax issues before the IRS during examinations, in appeals and as an advocate in trial and appellate litigation before the US Tax Court, US District Courts and US Court of Federal Claims. Mr. O’Brien’s tax controversy and litigation experience spans a broad range of areas, including transfer pricing controversies, advance pricing agreements, “tax shelter” disallowances, estate and gift tax valuations, research and development tax credits and change of accounting methods.

He also advises corporations, partnerships, and LLCs seeking corporate and tax advice in connection with various types of transactions, including mergers and acquisitions, restructurings, divestitures, leveraged buyouts, structured financings and oil and gas transactions.

“Shawn’s arrival establishes a local presence for Mayer Brown’s highly regarded Tax practice,” said Neil Wasserstrom, Partner-in-Charge of the Houston office. “His extensive experience representing energy companies on tax-related matters and deep understanding of the Houston and Texas markets are significant assets to the firm.”

Prior to joining Jackson Walker, Mr. O'Brien was a tax partner with Fulbright & Jaworski LLP.

Mr. O’Brien received an LLM degree from New York University School of Law, a JD degree from Loyola Law School and a BBA degree in accounting from Millsaps College.