If you are a Mexican entrepreneur forming a US LLC in 2026, the generic non-resident playbook gets you most of the way — and then four specifics force a local detour: the apostille is issued by the Secretaría de Relaciones Exteriores (SRE), the ITIN runs through an IRS-accredited CAA in Mexico instead of mailing your passport to Austin, the SAT expects you to report the foreign-LLC ownership through DIM and the declaración anual, and the address you give the IRS on Form SS-4 has to be parsed by US-formatted software that does not always like Mexican residential formats. Federal US law sets the baseline (IRS Publication 519 — U.S. Tax Guide for Aliens); the Mexican layer is what most providers do not explain in Spanish.
If you are forming a US LLC from Mexico in 2026, the generic non-resident playbook gets you most of the way — and then four specifics force a local detour. The apostille is issued by the Secretaría de Relaciones Exteriores (SRE), the ITIN runs through an IRS-accredited CAA in Mexico instead of mailing your passport to Austin, the SAT expects you to report the foreign-LLC ownership through DIM and the declaración anual, and the address you give the IRS on Form SS-4 has to be parsed by US software that does not always like Mexican residential formats. Federal US law sets the baseline IRS Publication 519 — U.S. Tax Guide for Aliens; the Mexican layer is what most providers do not explain in Spanish.
This guide assumes you have read the parent pillar US LLC for non-residents — the three universal gates of address, EIN, and bank. Here we cover what changes for a Mexican tax resident with an RFC.
1. Apostille via SRE
US banks and some state filings will eventually ask for a Mexican public document — typically a notarized passport copy or a power of attorney — bearing an apostille. The federal-document apostille in Mexico is issued by the SRE; state documents go through the state Secretaría de Gobierno SRE México — Apostilla de documentos públicos.
Sequence: identify exactly what the requesting party needs apostilled, notarize it before a notario público mexicano, then submit to the SRE apostille window in CDMX or a regional office. Fees and turnaround update annually — consult the SRE portal for the current schedule SRE México — Apostilla de documentos públicos.
Important: a Mexican notarization plus apostille does not replace USPS-commissioned notarization for Form 1583. USPS only accepts notaries commissioned in a US state, regardless of any apostille. The apostille is for the banking and state-filing layer. See the Form 1583 guide for the US-commissioned video-notary workflow.
2. ITIN via CAA-México
If your case requires an ITIN — typically because you receive US-source personal income or a specific bank asks for one — you do not have to mail your Mexican passport to Austin. The IRS maintains a network of Certifying Acceptance Agents (CAAs) in Mexico who verify your passport locally and certify the W-7 on your behalf IRS ITIN FAQ — Acceptance Agents for Non-Residents. Your passport never leaves the country, and the CAA prepares the W-7 in the format the IRS accepts on first review.
Most single-member non-resident LLCs do not actually need an ITIN to operate. The EIN identifies the LLC; online banks for non-residents typically accept the EIN plus a passport. Apply for the ITIN only when a concrete event makes it necessary.
3. EIN — Form SS-4 from a Mexican address
The mechanics are identical to the generic non-resident path: file Form SS-4 by fax or mail to the international EIN unit, write "Foreign" in the SSN/ITIN field for the responsible party, and wait four to six weeks for the CP 575 confirmation letter IRS — How to Apply for an EIN (international applicants).
The Mexico-specific tripwire is address formatting. The form has a US-style address block and a separate foreign-address block. Mexican addresses with Calle X #Y, Col. Z, C.P. NNNNN parse into the foreign block, but the IRS clerk will sometimes return the form if a line exceeds the character limit. Write the full address on a single line in the foreign block; do not split it across the US-format fields.
If you later move within Mexico, file Form 8822-B to update the responsible-party address — banks reconfirm this at periodic review.
4. The US business address — why your Mexican address won't work for banks
A common reflex is to use a relative's address in Texas or California as the LLC's principal place of business. This fails: online banks for non-residents check the entity address against US commercial-property registries, and a residential apartment resolves as residential on the verification scrape — the application is returned Mercury — Non-resident LLC eligibility (support docs, verified May 2026). Your Mexican residential address belongs in the responsible-party block, not the entity block. The entity needs a US commercial address that survives IRS, state, and bank verification — a licensed CMRA suite with a verifiable Street View presence and a notarized Form 1583 on file.
5. SAT reporting obligations
Mexico taxes its tax residents on worldwide income. Owning a US LLC adds reporting layers: the declaración informativa múltiple (DIM) with the relevant Anexo for entities and accounts held abroad, plus the declaración anual of foreign investments and bank accounts SAT México — Declaraciones (Declaración Informativa Múltiple para entidades extranjeras).
Three moving parts: (a) if the LLC is a single-member disregarded entity, US-source income flows through to you personally and the SAT will expect it on your declaración anual Código Fiscal de la Federación (CFF) — Art. 9 (residencia fiscal en México); (b) the existence and ownership of the foreign LLC must be disclosed on the DIM in the formation year and at any subsequent change; (c) US bank accounts held by the LLC trigger Anexo 4 (cuentas en el extranjero) — the filing deadline follows the SAT's current fiscal calendar SAT México — Declaración informativa de cuentas en el extranjero (Anexo 4).
Penalties for omission are not trivial. Engage a contador with cross-border experience before the first US-bank transaction settles. On the US side, the FinCEN beneficial-ownership filing under the Corporate Transparency Act applies to most LLCs and lists you as a beneficial owner 31 USC §5336 — Corporate Transparency Act (Beneficial Ownership Reporting) — free, online, accepts a Mexican passport.
6. Banking from Mexico — what online US banks accept
Online banks for non-residents publish written eligibility policies. Mexico-specific: proof of foreign residential address (a recent CFE light bill or comprobante de domicilio in your name typically passes) and the operational-presence documentation US banks have tightened since 2025 — lease, US-issued phone line, invoices to US clients, digital presence with a consistent US address Mercury — Non-resident LLC eligibility (support docs, verified May 2026), Relay — Eligibility requirements for non-US LLCs (support docs, verified May 2026).
There are no Mexico-specific blockers beyond the universal non-resident pattern. The risk is not nationality; it is address quality, EIN clarity, and operational-presence evidence. For the deep dive see the banking-acceptance guide.
7. Summary checklist
In order: secure a US commercial CMRA address (parent pillar), notarize Form 1583 with a US-commissioned video notary, file Florida or Wyoming articles, fax Form SS-4 with your Mexican address in the foreign-address block, file the FinCEN BOI report 31 USC §5336 — Corporate Transparency Act (Beneficial Ownership Reporting), apply for an ITIN through a CAA in Mexico only if needed IRS ITIN FAQ — Acceptance Agents for Non-Residents, apostille via SRE only what your bank actually requests, and set up SAT reporting with a Mexican contador before the first US-bank transaction settles.
FAQ
Do I need a Mexican notary's apostille for Form 1583?
No. USPS requires a notarization performed by a notary commissioned in a US state, regardless of any apostille. A Mexican notarization plus SRE apostille is useful for banks and state filings, not for the postal layer. Use the US-commissioned video-notary path for Form 1583 — see the Form 1583 guide.
Can I use my RFC instead of an EIN?
No. The RFC identifies you to the SAT. The EIN identifies your US LLC to the IRS. They are separate identifiers in separate tax systems. Your US LLC needs its own EIN issued via Form SS-4.
Does forming a US LLC change my Mexican tax residency?
No. Tax residency in Mexico is determined by Article 9 of the Código Fiscal de la Federación — primarily by where your habitual residence or center of vital interests is located Código Fiscal de la Federación (CFF) — Art. 9 (residencia fiscal en México). Owning a US LLC adds reporting obligations to your existing Mexican filing; it does not replace it.
Do I need to report my US LLC to the SAT?
Yes. Mexican tax residents must disclose foreign entities and foreign accounts on the DIM and the declaración anual in the years and amounts the SAT prescribes SAT México — Declaración informativa de cuentas en el extranjero (Anexo 4). Omitting the disclosure carries penalties.
Can a CAA in Mexico file my W-7 without me mailing my passport to Austin?
Yes. The IRS Certifying Acceptance Agent program allows an accredited agent in Mexico to verify your passport in person and certify the W-7 on your behalf, so your original passport never leaves Mexico IRS ITIN FAQ — Acceptance Agents for Non-Residents.
Need a Miami business address?
If you need a verifiable Miami business address that USPS, the IRS, and online banks for non-residents will accept on your LLC, we have three plans depending on what you want to delegate. Our Brickell address is a real CMRA with a verifiable suite and active lease. See the pricing page.
For other countries, see Colombia or the parent pillar.
Sources
Last updated: May 2026