How to choose a tax advisor: what to demand, what to distrust, and the questions that expose them

Choosing a tax advisor is the most asymmetric vendor decision of all: pick well and it pays for itself for years; pick badly and you find out three fiscal years later with a tax assessment, while the scheme's salesman no longer answers the phone. These are the standards you can — and should — demand, with their honest nuances, and the warning signs that no discount makes up for.

The four standards you can demand

1. Legality that is verifiable, not promised. Every proposal must come with a legal basis — an article, a rule, a criterion — and survive the acid test: that you can bounce it off your accountant, your auditor or another attorney and have them sign off. The serious advisor doesn't fear the second opinion; the scheme salesman sabotages it ("it's confidential, don't share it"). Opacity about the legal basis is the answer.

2. Fees lower than the benefit — with the benefit properly measured. In planning, the arithmetic rule is sound: if it costs 2 and saves 20, the advisor pays for himself. The nuance that separates us from the reels: be wary of "guaranteed savings" as a hook. Serious savings are estimated after a diagnostic, bounded by assumptions, and measured in avoided risk too — fines that never arrived, deductions that survived the audit, contingencies defused. Whoever guarantees you a percentage before seeing your numbers isn't estimating: he's selling.

3. Structural confidentiality. Professional privilege, confidentiality agreements and serious handling of your information — it's not a courtesy, it's a condition of the work. Your wealth structure in indiscreet hands is a risk in itself.

4. Backing in the defense — agreed from day one. The gold standard: whoever designs it, backs it. If the authority questions what your advisor proposed, he should show up for the clarification and the defense. Agree from the start, in writing, what the fee covers if there's a challenge — some firms absorb the defense of their own criteria and others quote it separately; both positions exist in the market, but finding out the model when the notice arrives means you negotiated it badly. The non-negotiable: that he doesn't leave you alone defending his idea.

In praise of the "by-the-book" accountant

A frequent business-owner complaint: "my accountant is too rigid." The honest answer: congratulations. Nobody ever got into a serious problem because of an accountant who was strict about the requirements — the 69-B (shell invoicing) files, the multimillion-peso assessments and the criminal cases are full, instead, of "flexible" accountants who could do it all. Your by-the-book accountant is the handbrake on your wealth; the tax strategist is the steering wheel. The roles complement each other: creativity belongs to the design of the structure — within the law — never to bookkeeping or compliance, where orthodoxy is the only virtue.

The technical test: roots, not branches

Good tax planning is boring on the surface and deep in its foundations. It's built on structural concepts — tax residence, permanent establishment, business reason, materiality, tax transparency, deferral, the legal concept of enajenación (transfer) — and not on trendy improvisations. Deferral is the perfect example: paying 100 five years from now instead of today, using mechanisms expressly provided for in the law, is worth a great deal of money without a single gray area. When you hear proposals that "flutter around the branches" — the union, the co-op, the magic payroll, the trust that can do anything — ask about the root: what concept in the law holds this up? The silence that follows is your answer. And one more signal, counterintuitive: the good tax advisor tells you no frequently — the one who approves everything isn't advising you; he's charging you to nod along.