Visión general

Clients turns to Diana Castro for her extensive experience in tax consultancy for national and international clients, primarily in indirect taxation, international taxation, customs matters, tax planning and administrative litigation.

She is a regular contributor to various publications, and author of several articles related to special customs regimes, international taxation and indirect taxation. Diana has a master's degree in Taxation, Public Finance and Development from the University of Rio de Janeiro-UERJ, and is also professor at PUC-Rio University in the Taxation of Digital Economy course.

Before joining Mayer Brown, Diana worked for a prominent international consulting firm and at Petrobras Transporte- Transpetro S/A.


  • Advises on M&A transactions associated with the leasing of bonded terminals for the sale of LNG in Brazil;
  • Diana analyzes contracts with E&P companies, international oil and gas service providers and suppliers of goods related to operations in Brazil;
  • Provides tax planning in the importation of floating power plants to Brazil and the structure of the transaction in the country;
  • Participates in the tax planning of bunker oil supply projects in Brazil;
  • Advises companies that operate in the generation of power with tax planning and the structuring of their operations in Brazil;
  • Analyzes tax and customs aspects in the integration and construction of FPSO in Brazil and abroad;
  • Advises IOCs, as well as their service providers with the structuring of their operations in Brazil;
  • Analyzes tax aspects in the constitution of a joint venture abroad;
  • Represents companies in tax litigation in assessments related to the tax classification of goods;
  • Secondee at an IOC as tax manager;
  • Provides tax advice and planning for Brazilian and foreign clients, including cross border transactions and analysis/applicability of Tax Treaties;
  • Represents companies in tax litigation related to state tax benefits;
  • Represents IOC in tax litigation challenging new tax levies in upstream industry;
  • Represents maritime support company in a tax assessment challenging the compliance of special customs regimes;
  • Provides customs and tax consultancy services related to the implementation of a natural gas regasification project;
  • Represents several international oil companies and international energy service providers in tax planning;
  • Reviews assessment and contract analysis of an Industry X company.
  • Advises on tax planning on cross border transactions;
  • Assists on day to day tax issues and indirect tax compliance issues;
  • Advises in customs field, encompassing the assistance with imports of assets under special customs regimes and procedures related;
  • Participates in relevant Due Diligences (M&A) processes and Corporate Reorganization projects.

Servicios e Industrias Relacionadas



  • Fundação Getúlio Vargas (FGV/RJ), MBA, Tax Law
  • Rocky Mountain Mineral Law Foundation, International Oil and Gas Law, Contracts, and Negotiations
  • Universidade do Estado do Rio de Janeiro, MA, Public Finance, Taxation and Development
  • Universidade Federal Fluminense (UFF), Bachelor of Law (JD equivalent)
  • Université Paris X Nanterre, Foreign Student
  • Universidade Estácio de Sá, BA, Accounting


  • Brazil


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