Doctors: stop handing the SAT 5 points of income tax — the structure that orders income, deductions and cash

"How can I pay less tax as a doctor?" is one of the questions we hear most — and the X-ray is almost always the same. The tax file of a successful health professional shows three findings: high income taxed in the most expensive brackets of the individual schedule, a meaningful share of cash payments that never enter the system, and everything — office, equipment, savings, risk — hanging off the same individual. All three are treatable. And it's worth starting with the good news: half of the tax problem other businesses suffer, you don't have.

What you've already won: your fees don't trigger VAT

Professional medical services that require a license are exempt from VAT (art. 15, sec. XIV LIVA) — and the law itself preserves the exemption when they are provided through a civil partnership (sociedad civil). The regulation narrows the club: physicians, veterinarians and dental surgeons (art. 41 RLIVA). That removes from your life the monthly mechanics of passing on, crediting and fighting for refunds of VAT. The nuance you do need to know: exempt is not 0% rate — the VAT you pay on your supplies and equipment is neither creditable nor refundable; it stays as a cost. Why that distinction is worth millions in other contexts is explained in 0% rate vs. exempt.

The real problem is income tax: 35% for doing it all as an individual

The individual income-tax schedule (art. 152 LISR) is progressive and punishes precisely the doctor who has already built a solid practice: the top brackets are taxed at 34% and 35% marginal. Meanwhile, a legal entity (persona moral) pays a flat 30% (art. 9 LISR). The structure that corrects the equation is well known in the sector and simple to state: the doctor + a civil partnership that provides medical services. You still perform the procedures yourself — your license, your reputation, your relationship with the patient — but the billing and operation (office, equipment, administrative staff, lease, insurance, training) live in the S.C. The result has three layers: profit is taxed at 30% instead of your 35% marginal; the universe of deductions widens — the S.C. deducts as a business what your individual self used to deduct grudgingly, and it also structures welfare benefits and partner compensation (an S.C.'s advances against profits are deductible for it, art. 94-II LISR in play); and your personal wealth is separated from professional risk, which in medicine is not theoretical. Your retirement nest egg should not live in the same pot that answers for your activity — where to place it (your S.C., your individual self or a third wealth vehicle) is a bespoke suit, not a recipe.

The cash: the elephant in the exam room

Here is the uncomfortable finding of the diagnosis: the cash you collect and don't declare is not a tax saving — it is a liability. Banks report to the SAT cash deposits exceeding MXN $15,000 a month (art. 55-IV LISR), your cards and spending reveal your real lifestyle, and the gap between what you spend and what you declare has a technical name and its own procedure: tax discrepancy, art. 91 LISR — with a criminal ending in the heavy cases (tax fraud, arts. 108 and 109 CFF). And the most underestimated practical effect: that money you cannot use — it doesn't buy a house without explaining its origin, it doesn't invest, it isn't inherited clean. The right structure gives every peso a legal front door with its CFDI (tax invoice), taxes it once at a reasonable rate, and turns the cash drawer into wealth that actually exists. Labels from the menu: a medical S.C. with real operation, contracts and accounting — defensible and the sector standard; a paper S.C. that only re-invoices without substance — risky (materiality and business reason, arts. 5-A CFF); structurally undeclared cash — red zone, on a clock. For practices that are starting out or bill little, the order may be different: RESICO (simplified regime) for individuals is taxed 1% to 2.5% on income up to MXN $3.5M — the comparative arithmetic is in the RESICO + VAT-free activity formula and you can run your numbers in the tax regime comparator.