Biography
Guillermo has more than 30 years as a lawyer, specifically in the fields of foreign trade and tax, providing services to large private companies in many sectors of industries.
He is a well-known lawyer in tax and trade litigation cases, he also advice companies in procedures that involved all the stages of a field audits performed by the Tax Authorities, including administrative and constitutional processes.
He worked at the Tax Administration Service (SAT) for almost 8 years as a Director in the Central Administration of Foreign Trade Audit in which he participated in multiple origin verifications procedures under the free trade agreements like the USMCA, now is successfully advising foreign companies from different sectors, which products were under review, and the Mexican companies who imports the goods reviewed.
Before and after the SAT he collaborated with prestigious law firms such as Baker & McKenzie and BDO.
Today Guillermo oversees the practice of International Trade and Customs.
- Successful attorney in numerous foreign trade and tax lawsuits held by foreign and Mexican entities against the Tax Authority in which the amounts claimed have reached billions of pesos.
- Legal negotiations with the tax authorities during audit processes to avoid substantial tax credits for companies.
- Constitutional procedures (Amparo) against various federal tax laws in which a positive result was obtained, avoiding the payment of unconstitutional taxes for clients.
- During my time on SAT I was able to negotiate with taxpayers to make them pay the unpaid taxes according to the law.
- Moreover, at the SAT I had the opportunity to collaborate with the Ministry of Economy in some treaty negotiations, such as the Free trade agreement with Japan and Central America.
- “Tariffs and Trade: Navigating the 2025 Global Landscape.” BDO Global February 19, 2025
- “Managing Indirect Tax Controversy”. EY Global Indirect Tax Symposium 2015, Barcelona, Spain.
- “México and The United States: More than Partners”. US-Mexican Bar Association 2011.
- Professor of the foreign trade module at the Faculty of Accounting at UNAM
- Mexico – Ban introduced on imports of goods made with forced labor. April 2023.
- “Certificaciones IVA e IEPS, ¿Pagarlas o defenderse?” Veritas magazine November 2020.
- “Criteria for Temporary Importation of Sensitive Goods Revised” October 2024
- Certified Expert managing Tax authority’s field
FisherBroyles is an international law firm practicing in a number of jurisdictions both in the United States and overseas through affiliated legal entities and branch offices of those entities. Legal services in Mexico are provided through Bravo Gutierrez & Münch, S.C., a member of FisherBroyles (the “Contracting Member”), with offices located in Mexico City, at Parque Lincoln, 5th Floor, Aristoteles 77, Polanco, Mexico City, Ciudad de Mexico 11560 and in Monterrey, at Blvd. Antonio L. Rodriguez 3000-5to piso Interior, 501 Torre Albia, Col. Santa Maria 64650 Monterrey, N.L.
The FisherBroyles Members engage in coordinated international legal practice and may share certain support services but are separate legal entities, each of which is solely responsible for its own work and is not responsible for the work of any other FisherBroyles Member. Each FisherBroyles Member is subject to the laws and regulations of the particular jurisdiction or jurisdictions in which it operates. Full details of the legal and regulatory status of each FisherBroyles Member are available on the FisherBroyles website.
The use of the name FisherBroyles is for description purposes only and does not imply that the Member Firms are in a partnership or are part of an LLP. The use of the word “partner” on any Member Firm’s website or in any other Member Firm materials refers to a partner or member of a FisherBroyles Member or an employee or consultant with equivalent standing and qualifications. You agree that your relationship is with the Contracting Member and not with another FisherBroyles Member unless otherwise confirmed in writing to you. You also agree that your relationship is not with any individual who is a member, employee, or consultant (including anyone we call a partner) of the Contracting Firm Member, who will therefore assume, to the extent permitted by law, no personal liability to you. Absent the explicit agreement and consent of both entities involved, no FisherBroyles Member is responsible for the acts or omissions of, nor has any authority to obligate or otherwise bind, any other FisherBroyles Member.
Guillermo Massieu
Partner
Credentials
Admissions
- Mexico
Education
Anahuac University 1996
U.S. Customs and Border Protection (CBP)
Instituto de Especialización para Ejecutivos
Prior Law Firm Experience
BDO Mexico
PDEA
PWC
Baker & McKenzie
Chevez, Ruiz, Zamarripa