Starting a business in Mexico
Everything begins at the SAT - the RFC, the e.firma appointment, and RESICO, the simplified regime that taxes small business at 1-2.5% of revenue.
Checked against the sources on 2026-08-30
Before anything else
Mexican formality lives at the SAT, the tax administration. A persona física registers business activity under the RFC (the tax ID), collects the e.firma - the cryptographic identity issued in person, by appointment, that signs everything after - and invoices through CFDI, the national e-invoice format that has no informal alternative: a business that cannot issue facturas barely exists to its customers.
The regime that changed small business is RESICO (Régimen Simplificado de Confianza): individuals with up to MXN 3.5 million of revenue pay income tax at 1% to 2.5% of receipts, withheld and settled with almost no deductions arithmetic. It is genuinely simple - the appointment queue for the e.firma is the hard part.
The legal shell
Persona física or company?
Persona física con actividad empresarial
The solo default, ideally inside RESICO.
Free at the SAT.
RESICO eligibility has exclusions (certain income mixes, partners in companies) and slips away if requirements lapse - filing discipline is the price of the low rate.
SAS
A one-person company, formed free online through the economy ministry, revenue-capped (a few million pesos, indexed).
$0 formation - the only free company in the hemisphere.
The cap, and banks treating young SAS accounts warily.
S. de R.L. / S.A. de C.V.
Partners, investors, scale.
Notary formation commonly MXN 10,000-25,000.
30% corporate rate and full accounting; the notary step makes this days-to-weeks, not minutes.
The sequence
RFC and e.firma at the SAT
Where: sat.gob.mx - preregister online, finish at the office by appointmentCost: $0Takes: The appointment wait is the bottleneck - book immediately
Bring CURP, ID and proof of address. The e.firma files (a certificate and key) leave with you on a USB stick; guard them - reissuing means another appointment.
Choose the regime - RESICO if it fits
Elected at registration or each January. Inside it, monthly declarations are near-automatic from your CFDIs; outside it, the actividad empresarial regime taxes profit at progressive rates with deductions.
Invoice by CFDI from day one
Facturas are stamped through the SAT’s systems (free tools exist; most use a certified provider for pesos a piece). IVA at 16% applies to most sales with monthly returns; clients will not pay without the factura, which keeps the system honest.
What it costs to start
| What | Amount |
|---|---|
| RFC + e.firma | $0 |
| RESICO income tax | 1-2.5% of revenue |
| CFDI stampingVia certified providers. | A few pesos per invoice |
| Notary companySAS: free. | MXN 10,000-25,000 |
The words on the forms
- SAT
- The tax administration - the centre of everything.
- RFC
- The tax ID every person and business carries.
- e.firma
- The cryptographic signature issued in person.
- CFDI / factura
- The compulsory e-invoice format.
- RESICO
- The 1-2.5% simplified trust regime to MXN 3.5M.
- IVA
- VAT at 16%, monthly.
- SAS
- The free online single-shareholder company.
- CURP
- The population ID the RFC builds on.
The traps
- Waiting weeks for an e.firma appointment because it was booked late.
- Losing the e.firma files.
- Falling out of RESICO through missed filings and landing in the general regime retroactively.
- Selling without CFDI capability and learning clients cannot deduct cash-register goodwill.
Where to check this yourself
- SATRFC, e.firma, RESICO, CFDI.
- gob.mx - Tu empresaThe free SAS formation.
This is a map, not legal or tax advice - and an honest one about how it was drawn: the Germany guide was written by a person who walked the route; most other countries were drafted with AI against the official sources and have not yet been walked by someone who did it. Laws change. Every guide carries the date it was last checked and the sources to check it yourself - and if you have been through one of these routes, your corrections are exactly what this handbook wants.