Administrative litigation
We care
about people.
Taxes are not just numbers. Our solutions make a difference to people and businesses.
FeaturedThe transition to IBS and CBSThe Firm
Academic rigor and strategy led by the partners themselves, case by case.
McNaughton Advogados is a tax law firm headquartered in São Paulo. Its partners combine academically recognized technical rigor with complementary careers, including work at firms specialized in complex tax matters and participation in the legislative debate on tax reform.
At McNaughton, every case receives a tailored legal strategy, designed and led directly by the partners. Our work is guided by ethics and by a commitment to solutions that create value for each business.
To care for people who need tax support.
To be a reference in federal tax litigation and strategic advice.
ExcellenceDeterminationObjectivityCreativityHumanismNonconformityEthics
Practice
Hypothetical situation
The company is not under audit, but wants to reduce risks, seize opportunities and prepare for changes such as the tax reform.
Hypothetical situation
The company is not under audit, but wants to reduce risks, seize opportunities and prepare for changes such as the tax reform.
How we help
We work side by side with management and the legal and tax teams, identifying risks, recovering credits and designing the most efficient and secure tax structure for the business.
Hypothetical situation
The company has received a notice, is under audit or has already been assessed by the tax authorities.
Hypothetical situation
The company has received a notice, is under audit or has already been assessed by the tax authorities.
How we help
We follow the procedure from the first notice, respond to the authorities’ requests and file the appropriate challenge and administrative appeals, including before CARF (the federal administrative tax court) and TIT (São Paulo’s tax court).
Hypothetical situation
The debt has been registered as overdue tax debt or is already being collected through a tax enforcement lawsuit.
Hypothetical situation
The debt has been registered as overdue tax debt or is already being collected through a tax enforcement lawsuit.
How we help
We assess whether it is more advantageous to negotiate the debt or challenge it in court, and we strategically manage each stage of the collection, focusing on protecting the company’s assets and operations.
Prevention and planning
Preventive advice to reduce risks
Legal review of the transactions, contracts and tax positions of a business or estate, to identify risks and address them before they turn into assessments or disputes.
Tax planning
Analysis of lawful alternatives to organize operations and structures more tax-efficiently, with legal certainty and proper documentation.
Tax credit recovery
Identifying, from a legal standpoint, overpaid or unduly paid taxes and unused credits, and recovering them through administrative or judicial channels.
Tax reform
An advisory committee for implementing the reform: assessing the impact on prices and contracts, reviewing contracts, using credits and monitoring the regulations.
Strategic tax litigation
Handling tax disputes in court with a strategy built for each case: preventing a demand before it is made, or defending assets against collection. Writs of mandamus, declaratory and annulment actions and defenses in tax enforcement proceedings, among others, are the tools, chosen according to the goal, the timing and the risk.
Other tailored solutions
Audit and assessment
Tax audit support
Guidance during the tax audit, in answering notices and delivering documents, so that communication failures do not lead to an assessment.
Administrative defense and appeals
A challenge to the tax assessment and appeals to the administrative bodies, such as CARF at the federal level and TIT in São Paulo. While under discussion, collection of the debt is suspended.
Installment plan
Splitting the debt into installments under ordinary or special programs. It suspends collection and allows the taxpayer to obtain a tax clearance certificate.
Other tailored solutions
Debt collection and tax litigation
Tax settlement
An agreement with the tax authorities to settle debts, possibly with reduced penalties and interest and longer terms, depending on each program or proposal.
Procedural agreement
An agreement with the government's attorneys to adjust how registered tax debts are collected, such as deadlines, guarantees and payment terms.
Strategic tax litigation
Handling tax disputes in court with a strategy built for each case: preventing a demand before it is made, or defending assets against collection. Writs of mandamus, declaratory and annulment actions and defenses in tax enforcement proceedings, among others, are the tools, chosen according to the goal, the timing and the risk.
Other tailored solutions
Hypothetical situation
You want to organize your assets, plan your family succession or simply understand your tax obligations before they become a problem.
Hypothetical situation
You want to organize your assets, plan your family succession or simply understand your tax obligations before they become a problem.
How we help
We advise on structuring personal and family wealth, succession planning and formal rulings requests to the tax authorities, giving your decisions legal certainty.
Hypothetical situation
You have received a notice from the Federal Revenue Service, your return was flagged for review, or you have been assessed.
Hypothetical situation
You have received a notice from the Federal Revenue Service, your return was flagged for review, or you have been assessed.
How we help
We help clear up pending issues with the tax authorities and, if needed, file the appropriate defense and administrative appeals, including installment arrangements for the debt.
Hypothetical situation
Your name is on the overdue tax debt register or you are facing a tax enforcement lawsuit.
Hypothetical situation
Your name is on the overdue tax debt register or you are facing a tax enforcement lawsuit.
How we help
We find the best way to settle the debt, by agreement or in court, and defend your assets against undue collection.
Prevention and planning
Preventive advice to reduce risks
Legal review of the transactions, contracts and tax positions of a business or estate, to identify risks and address them before they turn into assessments or disputes.
Wealth structuring
Organizing personal and family wealth tax-efficiently, including the analysis of holding companies and how assets are held.
Succession planning
Preparing the transfer of wealth between generations, with gifts and protective clauses and attention to the state inheritance and gift tax (ITCMD), to reduce future costs and disputes.
Formal ruling request
A request for the tax authorities to state officially how the law applies to a specific fact. While pending, it generally protects the taxpayer from penalties on the matter.
Legal opinion
A reasoned technical opinion on a specific tax question. It guides the decision and documents the rationale, supporting the client's position.
Other tailored solutions
Audit and assessment
Tax audit support
Guidance during the tax audit, in answering notices and delivering documents, so that communication failures do not lead to an assessment.
Administrative defense and appeals
A challenge to the tax assessment and appeals to the administrative bodies, such as CARF at the federal level and TIT in São Paulo. While under discussion, collection of the debt is suspended.
Installment plan
Splitting the debt into installments under ordinary or special programs. It suspends collection and allows the taxpayer to obtain a tax clearance certificate.
Other tailored solutions
Debt collection and tax litigation
Tax settlement
An agreement with the tax authorities to settle debts, possibly with reduced penalties and interest and longer terms, depending on each program or proposal.
Strategic tax litigation
Handling tax disputes in court with a strategy built for each case: preventing a demand before it is made, or defending assets against collection. Writs of mandamus, declaratory and annulment actions and defenses in tax enforcement proceedings, among others, are the tools, chosen according to the goal, the timing and the risk.
Other tailored solutions
The transition to IBS and CBS
Tax reform is changing how consumption is taxed in Brazil. We bring the experience of those who took part in the debate that produced the new rules, and we follow every stage of the transition.
See the full transition- Assessment of the impact on prices and contracts
- Advisory committee for implementing the reform
- Preventive advice to reduce risks
- Use of credits under the new regime
- Monitoring of the regulations
Hypothetical situation
The company is not under audit, but wants to reduce risks, seize opportunities and prepare for changes such as the tax reform.
How we help
We work side by side with management and the legal and tax teams, identifying risks, recovering credits and designing the most efficient and secure tax structure for the business.
Possible solutions
Legal review of the transactions, contracts and tax positions of a business or estate, to identify risks and address them before they turn into assessments or disputes.
Analysis of lawful alternatives to organize operations and structures more tax-efficiently, with legal certainty and proper documentation.
Identifying, from a legal standpoint, overpaid or unduly paid taxes and unused credits, and recovering them through administrative or judicial channels.
An advisory committee for implementing the reform: assessing the impact on prices and contracts, reviewing contracts, using credits and monitoring the regulations.
Handling tax disputes in court with a strategy built for each case: preventing a demand before it is made, or defending assets against collection. Writs of mandamus, declaratory and annulment actions and defenses in tax enforcement proceedings, among others, are the tools, chosen according to the goal, the timing and the risk.
Other tailored solutions
Hypothetical situation
The company has received a notice, is under audit or has already been assessed by the tax authorities.
How we help
We follow the procedure from the first notice, respond to the authorities’ requests and file the appropriate challenge and administrative appeals, including before CARF (the federal administrative tax court) and TIT (São Paulo’s tax court).
Possible solutions
Guidance during the tax audit, in answering notices and delivering documents, so that communication failures do not lead to an assessment.
A challenge to the tax assessment and appeals to the administrative bodies, such as CARF at the federal level and TIT in São Paulo. While under discussion, collection of the debt is suspended.
Splitting the debt into installments under ordinary or special programs. It suspends collection and allows the taxpayer to obtain a tax clearance certificate.
Other tailored solutions
Hypothetical situation
The debt has been registered as overdue tax debt or is already being collected through a tax enforcement lawsuit.
How we help
We assess whether it is more advantageous to negotiate the debt or challenge it in court, and we strategically manage each stage of the collection, focusing on protecting the company’s assets and operations.
Possible solutions
An agreement with the tax authorities to settle debts, possibly with reduced penalties and interest and longer terms, depending on each program or proposal.
An agreement with the government's attorneys to adjust how registered tax debts are collected, such as deadlines, guarantees and payment terms.
Handling tax disputes in court with a strategy built for each case: preventing a demand before it is made, or defending assets against collection. Writs of mandamus, declaratory and annulment actions and defenses in tax enforcement proceedings, among others, are the tools, chosen according to the goal, the timing and the risk.
Other tailored solutions
Hypothetical situation
You want to organize your assets, plan your family succession or simply understand your tax obligations before they become a problem.
How we help
We advise on structuring personal and family wealth, succession planning and formal rulings requests to the tax authorities, giving your decisions legal certainty.
Possible solutions
Legal review of the transactions, contracts and tax positions of a business or estate, to identify risks and address them before they turn into assessments or disputes.
Organizing personal and family wealth tax-efficiently, including the analysis of holding companies and how assets are held.
Preparing the transfer of wealth between generations, with gifts and protective clauses and attention to the state inheritance and gift tax (ITCMD), to reduce future costs and disputes.
A request for the tax authorities to state officially how the law applies to a specific fact. While pending, it generally protects the taxpayer from penalties on the matter.
A reasoned technical opinion on a specific tax question. It guides the decision and documents the rationale, supporting the client's position.
Other tailored solutions
Hypothetical situation
You have received a notice from the Federal Revenue Service, your return was flagged for review, or you have been assessed.
How we help
We help clear up pending issues with the tax authorities and, if needed, file the appropriate defense and administrative appeals, including installment arrangements for the debt.
Possible solutions
Guidance during the tax audit, in answering notices and delivering documents, so that communication failures do not lead to an assessment.
A challenge to the tax assessment and appeals to the administrative bodies, such as CARF at the federal level and TIT in São Paulo. While under discussion, collection of the debt is suspended.
Splitting the debt into installments under ordinary or special programs. It suspends collection and allows the taxpayer to obtain a tax clearance certificate.
Other tailored solutions
Hypothetical situation
Your name is on the overdue tax debt register or you are facing a tax enforcement lawsuit.
How we help
We find the best way to settle the debt, by agreement or in court, and defend your assets against undue collection.
Possible solutions
An agreement with the tax authorities to settle debts, possibly with reduced penalties and interest and longer terms, depending on each program or proposal.
Handling tax disputes in court with a strategy built for each case: preventing a demand before it is made, or defending assets against collection. Writs of mandamus, declaratory and annulment actions and defenses in tax enforcement proceedings, among others, are the tools, chosen according to the goal, the timing and the risk.
Other tailored solutions
Tax reform is changing how consumption is taxed in Brazil. We bring the experience of those who took part in the debate that produced the new rules, and we follow every stage of the transition.
- Assessment of the impact on prices and contracts
- Advisory committee for implementing the reform
- Preventive advice to reduce risks
- Use of credits under the new regime
- Monitoring of the regulations
01Prevention and planning
Legal review of the transactions, contracts and tax positions of a business or estate, to identify risks and address them before they turn into assessments or disputes.
Learn more — Preventive advice to reduce risksA reasoned technical opinion on a specific tax question. It guides the decision and documents the rationale, supporting the client's position.
Learn more — Legal opinionA request for the tax authorities to state officially how the law applies to a specific fact. While pending, it generally protects the taxpayer from penalties on the matter.
Learn more — Formal ruling requestAnalysis of lawful alternatives to organize operations and structures more tax-efficiently, with legal certainty and proper documentation.
Learn more — Tax planningOrganizing personal and family wealth tax-efficiently, including the analysis of holding companies and how assets are held.
Learn more — Wealth structuringPreparing the transfer of wealth between generations, with gifts and protective clauses and attention to the state inheritance and gift tax (ITCMD), to reduce future costs and disputes.
Learn more — Succession planningIdentifying, from a legal standpoint, overpaid or unduly paid taxes and unused credits, and recovering them through administrative or judicial channels.
Learn more — Tax credit recoveryAn advisory committee for implementing the reform: assessing the impact on prices and contracts, reviewing contracts, using credits and monitoring the regulations.
Learn more — Tax reformOther tailored solutions
02Audit and assessment
Guidance during the tax audit, in answering notices and delivering documents, so that communication failures do not lead to an assessment.
Learn more — Tax audit supportA challenge to the tax assessment and appeals to the administrative bodies, such as CARF at the federal level and TIT in São Paulo. While under discussion, collection of the debt is suspended.
Learn more — Administrative defense and appealsSplitting the debt into installments under ordinary or special programs. It suspends collection and allows the taxpayer to obtain a tax clearance certificate.
Learn more — Installment planOther tailored solutions
03Collection and litigation
An agreement with the tax authorities to settle debts, possibly with reduced penalties and interest and longer terms, depending on each program or proposal.
Learn more — Tax settlementAn agreement with the government's attorneys to adjust how registered tax debts are collected, such as deadlines, guarantees and payment terms.
Learn more — Procedural agreementHandling tax disputes in court with a strategy built for each case: preventing a demand before it is made, or defending assets against collection. Writs of mandamus, declaratory and annulment actions and defenses in tax enforcement proceedings, among others, are the tools, chosen according to the goal, the timing and the risk.
Learn more — Strategic tax litigationOther tailored solutions
Partners

Charles W. McNaughton
Lawyer (PUC/SP), with a master’s degree and a doctorate in law from PUC/SP and postdoctoral studies at the University of São Paulo (USP). For more than 20 years he has practised tax law, in advisory work and litigation, with a focus on strategic cases, as well as M&A and non-profit matters. He has served as a judge on the São Paulo Tax Court (TIT/SP), taught in the IBET master’s programme, in PUC-SP’s graduate programme and at Insper, and sat for ten years on the Tax and Penalties Council of São Bernardo do Campo. He is the author of Curso de IBS e CBS, Curso de IRPF and other books, some translated into other languages, and a columnist for Conjur.

Marina Tófoli
Lawyer (UNIMAR), specialist in tax law (IBET), with courses in Taxation of Corporate Structures and Transactions (FGV) and in Tax Planning (IBET). She practises tax law. A former university lecturer, she brings in-house experience as head of legal.

Pedro Cruz
Lawyer (UFBA), with an LLM in Tax Law (FGV) and an MBA in Tax Management (USP). He practises tax law and is a tutor in PUC/SP’s graduate programme in tax law. He brings in-house experience from a multinational company, where he was responsible for part of the administrative tax litigation portfolio and, in tax strategy, supported the implementation of the tax reform and worked on tax affairs.

Roberta Wink
Law degree from the Federal University of Mato Grosso do Sul (UFMS). Currently studying Accounting at FIPECAFI. Graduate certificate in Tax Law from the Brazilian Institute of Tax Studies (IBET) and in Business Management and Planning from FAE Business School. Master's in Tax Law from IBET. Teaching assistant for the “Tax Enforcement” course in IBET's master's program in tax law. Author of academic articles. Practices in tax advisory and in administrative and judicial tax litigation.

Thais Oliveira
Lawyer (USJT), specialist in tax law (IBET), with an extension course in Succession and Wealth Planning (APET). She practises tax law, with solid experience in administrative and judicial tax litigation.
Of Counsel

Cely A. M. McNaughton
Lawyer (Mackenzie) with a bachelor’s degree in Philosophy (USP). She practises civil law.

John F. McNaughton
Lawyer, born in New York, with initial studies at Hunter College. Law degree (PUC-SP) and specialisation in Commercial Law (USP). He practises business law. He co-authored Exporting to the United States of America and China Pós-OMC: Direito e Comércio, was technical reviewer of the Portuguese edition of a World Bank publication on competition policy, and has been a correspondent for Latin American Law & Business and Inter-American Trade.
Every case receives a tailored strategy.
Publications
Articles
Administrative litigation
Higher courts
The role of the Superior Court of Justice in tax law
Tax interpretation
Interpretations that render tax rules ineffective
Tax reform
IBS, CBS and the export of services
Tax reform
On the concept of services in Brazil’s consumption tax reform
Corporate income tax
Taxation of ICMS incentives: following binding precedent and the law is not a “thesis”
Intellectual services
Article 129 of Law 11,196/05 as a legal fiction
Tax reform
There is no personal use or consumption in a taxpayer’s business activity
Tax reform
On IBS and CBS as consumption taxes
Tax reform
On the IBS regulation and refunds under the tax reform
Tax reform
Towards a new theory of the tax obligation for IBS and CBS
Books
Curso de IBS e CBS
MCNAUGHTON, Cristiane Pires; MCNAUGHTON, Charles William. Curso de IBS e CBS: de acordo com a Emenda Constitucional 132/23 e com as Leis Complementares 214/25 e 227/26. 2. ed. rev., atual. e ampl. São Paulo: Noeses, 2026.
Curso de IRPF
MCNAUGHTON, Charles William. Curso de IRPF. 2. ed. rev., atual. e ampl. São Paulo: Noeses, 2022.
- 01Part I – The legal regime of personal income tax (IRPF) in the Constitution
- 02Part II – The legal regime of IRPF in the National Tax Code
- 03Part III – The rule of incidence of IRPF – annual adjustment in federal legislation
- 04Part IV – Final taxation, exclusive withholding at source and treatment as a legal entity
- 05Part V – Treatment of individuals as legal entities
Elisão e norma antielisiva
MCNAUGHTON, Charles William. Elisão e norma antielisiva: completabilidade e sistema tributário. São Paulo: Noeses, 2014.
- 01Completeness and the legal system
- 02Completability and the tax system
- 03Completability and private law: the interaction between tax law and private law
- 04Tax avoidance
- 05Tax evasion
- 06Anti-avoidance rules
- 07Anti-evasion rules
- 08Avoidance in individual cases: a critical analysis of the business purpose requirement
- 09Limits of avoidance and of the anti-avoidance rule
- 10Conclusions
Jerarquía y sistema tributario
MCNAUGHTON, Charles William. Jerarquía y sistema tributario. 2. ed. Santiago: Ediciones Olejnik, 2021.
Hierarquia e sistema tributário
MCNAUGHTON, Charles William. Hierarquia e sistema tributário. São Paulo: Quartier Latin, 2011.
- 01Hierarchy and the theory of language
- 02Hierarchy and the general theory of law
- 03Democracy and legality in tax law
- 04The principle of legality and presumptions in tax law
- 05Hierarchy among legislative norms: general considerations
- 06Hierarchy: entrenchment clauses versus amendments
- 07Hierarchy among tax norms of the total order and the partial orders
- 08Procedural hierarchy
- 09Concluding synthesis
Fusões e aquisições
GAUDÊNCIO, Samuel Carvalho; MCNAUGHTON, Charles William. Fusões e aquisições: prática jurídica no M&A. 3. ed. Rio de Janeiro: Lumen Juris, 2019.
Manual do Imposto de Renda da Pessoa Jurídica – IRPJ
MCNAUGHTON, Charles William; JR., Pedro Anan. Manual do Imposto de Renda da Pessoa Jurídica – IRPJ: teoria e prática. São Paulo: Intelecto, 2016.







