Tax lawyer.
When the argument decides the outcome.

What a tax lawyer does

A tax lawyer works where taxation meets the law: interpreting tax legislation, building the argument that supports a saving or a defense, and standing behind it before the administration and the courts. Unlike those who merely comply with an obligation, a tax attorney questions whether and how a tax is owed — and turns that analysis into financial results and reduced risk.

In practice, this comes down to four deliverables:

• Lawful savings — designing the operation, tax regime, and corporate structure to pay only the tax legally due, grounded in a legal argument rather than an aggressive position.
• Recovery — identifying and reclaiming credits and overpayments going back five years (the statute of limitations), administratively or in court.
• Defense — challenging tax assessments and litigating when a charge is improper, from the administrative proceeding through to the courts.
• Certainty — giving predictability to business decisions by mapping liabilities before the tax authority identifies them.

Advisory and litigation: the two fronts

Tax law practice divides into two fronts that, in a boutique firm, move together — the same team that designs the argument is the one that defends it if the tax authority challenges it.

On the advisory side, the tax lawyer works before any dispute: tax planning and choice of tax regime, recovery of credits on PIS/COFINS, ICMS, and IPI, alignment with the tax reform (IBS and CBS), transfer pricing, and compliance. On the litigation side, the work begins once a charge exists: defense against tax assessments, administrative proceedings, CARF, tax enforcement (execução fiscal), writ of mandamus (an expedited constitutional remedy against unlawful tax acts), and litigating tax positions in the courts.

When a company needs a tax lawyer

A company turns to a tax lawyer when a tax decision stops being routine and starts carrying real value and risk. The most common scenarios:

• It has received a tax assessment or notice from the tax authority and needs a technical defense within the deadline.
• It is overpaying tax and wants to review its burden and recover credits going back five years.
• It is about to restructure — a holding company, merger, acquisition, or succession — and needs a structure built on legal certainty.
• It needs to prepare for the tax reform and understand the impact of IBS/CBS on its margins and cash flow.
• It operates across borders and faces transfer pricing, treaties, and the taxation of multinationals.
• It wants predictability — a diagnostic that maps liabilities and opportunities before an audit.

Areas of practice

TaxUp covers the full cycle of corporate taxation across seven integrated practice areas:

• Tax credit recovery — PIS/COFINS, ICMS, ICMS-ST, IPI, and out-of-period credits.
• Tax planning — tax regime, corporate restructuring, holding companies, and incentives.
• Tax reform — transition to IBS and CBS, split payment, and financial credit.
• Transfer pricing — transfer pricing rules aligned with the OECD standard and Pillar Two.
• Tax litigation — defense against assessments, CARF, tax enforcement, and writ of mandamus.
• Tax compliance — tax reporting obligations, SPED, and tax governance.
• International tax planning — market entry into Brazil, cross-border remittances, and treaties.

Tax lawyer or accountant?

These are complementary roles, not competing ones. The accountant calculates the taxes, keeps the books, and handles the required tax filings — the day-to-day of compliance. The tax lawyer works at the legal layer: building the argument, deciding whether a charge is owed, issuing an opinion grounded in legal certainty and — an activity reserved by law to licensed lawyers — challenging the assessment and appearing in court. When an argument, a dispute, or a restructuring is at stake, it is the lawyer who answers for it. At TaxUp, the two disciplines work side by side: accounting rigor supports the legal argument.

How to choose a tax lawyer

Tax law is one of the most technical and fast-changing areas of Brazilian law. When choosing a tax lawyer, four signals separate depth from the generic:

• Verifiable admission and specialization — a lawyer admitted to the OAB (Brazilian Bar) and in good standing, with training and specialization in tax law.
• Whoever signs is whoever handles it — the senior lawyer runs the case, without handing it off to junior staff or switching the person in charge midway.
• An argument, not a promise — the proposed saving rests on statute, case law, and citable precedent, not on a risky loophole.
• Command of the current agenda — the tax reform, transfer pricing, and the leading tax issues now pending before the STF, STJ, and CARF.

Who runs the cases

At TaxUp, every engagement is led by the lawyers who own the firm — the boutique model, in which the senior lawyer is at the table from start to finish.

• Rafael Belisário (OAB/SP 552.190) — a lawyer who earned his law degree at the University of São Paulo (Largo Sao Francisco), with a double degree from the Université Jean Moulin Lyon 3 (France). His practice concentrates on transfer pricing, Pillar Two, and the tax reform.
• Lucas Braz (OAB/PB 27.740) — holds a master's in Tax Law from the University of São Paulo, with a specialization in tax law (IBET) and a focus on the tax reform, indirect taxes, and tax credit recovery.

The full team profile is available at who runs the engagements, and the firm's positioning at about TaxUp.

How the Engagement Works in Practice

A tax lawyer's engagement at TaxUp follows four clear stages: a free diagnostic, a fully reasoned legal opinion, execution, and ongoing monitoring with regular reporting. From the very first conversation, the client knows what will happen, in what order, and what the deliverable is at each stage — because a predictable process is part of the deliverable.

1. Free 30-minute diagnostic

Everything starts with a 30-minute conversation, free of charge and with no commitment. In it, the team maps the company's tax regime, the concrete problem (a tax assessment, a structuring question, a suspected overpayment) and evaluates whether there is, in fact, a well-founded matter to pursue. If there is not, the firm says so with the same candor — and the conversation ends there, with no invoice. Simply book a time slot.

2. A fully reasoned legal opinion or claim theory

Once the opportunity or risk is identified, the team formalizes the analysis in a written legal opinion: what the legal theory is, which statutory and case-law grounds support it, what the possible scenarios are, and the risks of each path. The client decides with the complete map in hand — never on the strength of a generic promise.

3. Administrative or judicial execution

Once the path is approved, the firm's attorneys and consultants execute it: an administrative defense, a judicial measure, a refund claim, or a restructuring, as the case requires. The choice of forum is never off the shelf — it depends on the subject matter, the available evidence, and the urgency, and it is explained to the client before the first filing. Each front is detailed on the tax litigation and recovery of credits pages.

4. Monitoring and reporting

A case filed is not a case closed. The team tracks every docket entry, meets every procedural deadline, and reports progress in business language — what happened, what it means, and what the next step is. The goal is that the client does not have to ask "where does my case stand" — the reporting routine is designed so the information arrives before the question does. To meet the professionals who lead this work, visit the attorneys and consultants page.

Fees: How a Tax Lawyer Charges

A tax lawyer typically charges under one of four models: a fixed project fee, a monthly consulting retainer, a success fee, or a hybrid combination — and the right model depends on the nature of the work, not on the size of the client. Understanding the logic of each format before engaging avoids surprises and aligns the incentives of company and firm.

Fixed project fee

Suited to deliverables with a closed scope: a legal opinion, a restructuring, a specific defense. The amount is set before the work begins, based on the complexity and the estimated team time. The company knows exactly what it will invest and what it will receive.

Monthly retainer

It works like an on-demand tax legal department: the company pays a monthly amount and has ongoing access to the attorneys and consultants for questions, reviews, and recurring follow-up. It is the natural format for companies that need permanent tax compliance or operate in a sector under constant regulatory change.

Success fee

Under the success fee (contingency) model, compensation is a percentage of the result actually obtained — a common arrangement in tax credit recovery, where the firm is paid only if the company recovers. The percentage varies with the legal theory, the risk, and the amounts involved, and it is always agreed in writing before the work begins.

Hybrid

Many engagements combine formats: a reduced fixed fee to cover the initial structuring plus a success percentage on the outcome, for example. The hybrid splits the risk between the parties and is often the most balanced design for medium-term claims.

At TaxUp, the first conversation is always free — and the fee proposal is presented only after the diagnostic, once the problem, the legal theory, and the model that fairly compensates the work on both sides are known. To get started, use the contact page.

The Deadlines That Decide a Tax Case

Two deadlines decide most Brazilian tax cases: 20 business days to file the administrative defense (Supplementary Law 227/2026) and 5 years to recover overpaid taxes (Brazilian Tax Code — CTN, art. 168, I). In tax matters, a missed deadline is a lost right — the strongest defense in the world is worth nothing if filed one day late. That is why TaxUp's guidance is unequivocal: the company should engage a tax lawyer the day the tax assessment arrives, not the following week.

Administrative defense: 20 business days

The deadline to challenge a federal tax assessment is now 20 business days from notification: Supplementary Law 227/2026, signed into law on January 13, 2026, amended Decree 70.235/1972, replacing the former 30 calendar days. The same change reached the voluntary appeal to CARF — Brazil's federal administrative tax court — which now also runs for 20 business days. It sounds like more time, but it is no cushion: gathering documents, analyzing the assessment, and building the defense consumes that calendar quickly.

Transition rules — extra caution

Transition rules in 2026 change how the deadline is counted depending on the notification date — and miscounting a deadline in this period is one of the costliest mistakes a company can make. It is one of the first points the team verifies in any tax litigation matter, where the transition regime is detailed.

The 5-year window to recover

A company that overpaid taxes has 5 years, counted from the undue payment (CTN, art. 168, I), to recover the amounts — and this limitation period runs without suspension, even while an administrative dispute is pending. Every month of waiting is a month of credit that expires at the back end of the window. The full path is on the recovery of credits page.

Tax Avoidance vs. Tax Evasion: The Boundary of Lawful Practice

The difference between tax avoidance and tax evasion is the difference between tax savings and a crime — and it is the boundary that defines where a serious tax lawyer operates. Anyone engaging counsel needs to understand this line, because it separates the planning that protects the company from the planning that puts it at risk.

Avoidance: lawful savings, before the taxable event

Lawful tax avoidance is the set of legitimate business decisions, taken before the taxable event, that reduce the tax burden through choices the law itself authorizes. It is a taxpayer's right, grounded in the constitutional principle of tax legality (Federal Constitution, art. 150, I) and in the freedom of economic enterprise (art. 170). Choosing the appropriate tax regime, organizing operations efficiently, using incentives provided by statute — all of this is avoidance, and it is precisely the object of well-executed tax planning.

Evasion: unlawful, after the taxable event

Tax evasion is concealment or falsification that reduces taxation after the taxable event has already occurred — and it is a tax crime in Brazil (Law 8.137/90, punishable by 2 to 5 years' imprisonment). Unreported revenue, sham invoices, forged documents, and simulated transactions are the classic examples. No amount of savings justifies that path: beyond the criminal sanction, the company is exposed to aggravated penalties and to the destruction of its reputation.

The gray zone — and the test that resolves it

Between the two extremes lies what Brazilian doctrine calls elusão: a structure lawful in form but simulated in substance, which the tax authority may disregard. The dividing line is the economic substance and the business purpose of the transaction — a structure that exists only on paper does not hold.

TaxUp works exclusively with well-grounded positions: every recommendation has an identified legal basis, mapped case law, and real economic substance. If a saving is only possible by crossing that line, the firm's answer is no — and that answer is also part of the service. Learn more about this philosophy on the about TaxUp page.

In-House Counsel, Accountant, or Outside Firm?

In-house counsel, the accountant, and the outside law firm do not compete with one another — each solves a different type of problem, and a mature company uses all three in coordination. The right question is not "which one to choose" but "which problem am I trying to solve right now." The accountant's role — the irreplaceable guardian of the day-to-day tax routine — has already been addressed in the comparison between the tax lawyer and the accountant; here the axis is a different one: in-house legal versus outside firm.

When in-house counsel makes sense

Large companies with a constant volume of tax matters justify an in-house tax lawyer: someone who knows the operation from the inside, filters risks at the source, and coordinates outside providers. The in-house limit is depth: no single professional masters, at the same time, litigation, corporate reorganization, transfer pricing, and Brazil's Tax Reform at the level each front demands.

When the boutique outside firm comes in

The boutique outside firm delivers depth on demand, without the fixed cost of keeping that structure in-house. The company brings in specialists the moment the problem appears — a significant tax assessment, a tax credit recovery claim, a restructuring — and pays for the work, not for the permanent availability of a senior team.

The model that works: all three together

In TaxUp's practice, the best outcome comes from joint work: the accountant supplies the data and knows the numbers; in-house counsel (where it exists) contextualizes the operation; and the outside firm brings the legal theory, the strategy, and the specialized execution. The firm routinely works in partnership with clients' accountants and legal departments — no turf disputes, with a clear division of roles. To discuss which design fits your company, book a conversation.

The Tax Lawyer at Each Stage of the Company's Life

Every company crosses paths with tax law at predictable moments of its life cycle — and at each of them the tax lawyer plays a different role. Recognizing these moments before they turn into emergencies is what separates the company that plans from the one that merely reacts.

Incorporation and choice of tax regime

The company's first tax decision is the choice of regime — and getting it wrong means paying more tax from the first month of operation. Tax planning at the outset costs a fraction of what correcting course later does.

Growth and change of regime

When revenue grows, the regime that once fit no longer does: thresholds are exceeded, margins shift, and the structure needs to be revisited. It is the moment to model scenarios and to install tax compliance routines that match the company's new scale.

M&A and corporate reorganization

Mergers, acquisitions, and reorganizations surface hidden liabilities and open structuring opportunities — the corporate design of the transaction determines the business's tax burden for years. The tax attorney comes in before signing, in the due diligence and in modeling the structure.

Tax audit and assessment

The tax assessment arrives and the clock starts running: the administrative defense has a short deadline, and the strategy defined in the first days shapes the entire remainder of the case. This is tax litigation territory.

Going international

Operating cross-border — importing, exporting, transacting with related parties — activates new layers of complexity, from transfer pricing to international tax treaties. International tax planning structures these operations before the tax authority questions them.

Succession and holding structures

At maturity, the agenda turns to asset protection and succession: family holding companies and reorganizations that prepare the orderly, efficient transfer of wealth — always within the law, with structures of real substance.

The Agenda Redefining Tax Practice in Brazil

The coming decade will be the most intense for Brazilian tax practice in generations: the Tax Reform, the new OECD-aligned transfer pricing rules, and the post-precedent litigation wave are transforming the rules, the procedures, and the opportunities all at once. A company hiring a tax lawyer today is hiring someone to navigate that transition.

Tax Reform: 7 years of two systems running at once

Since January 1, 2026, Brazil has been living through the transition that replaces PIS, COFINS, ICMS, and ISS with a dual VAT — the federal CBS and the state-and-municipal IBS — plus the Selective Tax, under Constitutional Amendment 132/2023 and Supplementary Law 214/2025. Until 2033, companies will operate two tax systems simultaneously, and every pricing, contract, and credit decision runs through the new design — work that demands continuous legal monitoring. The full transition timeline is on the Tax Reform page.

Transfer pricing under the OECD standard

The alignment of Brazil's transfer pricing rules with the OECD standard changed the logic for anyone transacting with related parties abroad: documentation, methods, and comparability analyses now follow the international yardstick. It is a technical discipline that requires a dedicated specialist — the topic is covered in depth on the transfer pricing page.

Post-precedent litigation: executing what the courts decided

The landmark tax cases decided in recent years opened a new phase: converting superior-court rulings into concrete credits, with calculation, evidence, and procedural strategy. That is the work of tax litigation and recovery of credits — and the 5-year window does not wait for those who hesitate.

Tax lawyer in São Paulo

In São Paulo — TaxUp's corporate seat — clients are received by appointment at Av. Brigadeiro Faria Lima 3144, in the heart of the financial district. The team serves mid-sized and large São Paulo companies across the full tax agenda — from recovering ICMS and PIS/COFINS credits to defending against state and federal assessments and litigating before CARF and the São Paulo state administrative tax tribunal (TIT). Meetings are held in person or remotely, depending on the matter. See the address and reach the São Paulo office.

Tax lawyer in Rio de Janeiro

In Rio de Janeiro, TaxUp meets clients by appointment at Av. das Américas 3693, in Barra da Tijuca. The team advises Rio companies on tax planning, tax credit recovery, administrative and judicial litigation, and alignment with the tax reform, with the same senior leadership as the firm's other locations. See the address and reach the Rio de Janeiro office.

Tax lawyer in Brasília

In Brasília, clients are received by appointment at SCS Q.09 Bloco C Torre C, in Asa Sul — minutes from the higher courts and the federal authorities. Its proximity to the STF, the STJ, and CARF supports close monitoring of the leading tax issues and the most significant federal tax litigation. See the address and reach the Brasília office.