Filing a return before the deadline is the minimum you should expect from an accounting firm in Mexico. It is also the end of the monthly process. The real work starts with CFDI invoices, bank reconciliations, payroll, tax calculations and evidence for every amount reported.
Ask to see the monthly handoff
A useful way to compare firms is to request an example of the monthly close package with confidential data removed. It should make responsibilities, pending items, filed returns and retained evidence easy to identify. A clear handoff says more about the service than a long list of generic deliverables.
Be wary of a tax savings promise made before the firm sees your records, checks your tax regime or understands how the business collects and pays. A reliable firm can tell you what it reviews, what you receive after each close and how it reports a difference before filing.
What to ask for before hiring
Ask for a redacted sample of a monthly close. It should show the CFDI and bank review, filings completed, SAT acknowledgments, calculations and open items. A firm that quotes "tax filings" without asking about your regime, invoice volume, bank accounts, payroll or open SAT matters does not yet know the workload.
| Area | Evidence to request |
|---|---|
| Scope | List of filings, CFDI work, payroll, Tax Mailbox monitoring and reports included |
| Monthly close | Acknowledgments, working papers, reconciliations and open-item list |
| SAT differences | Named owner, response deadline and documentation process |
| Security | Method for protecting e.firma files, passwords and business records |
Scope changes with the business
| Operation | Accounting work to confirm |
|---|---|
| Freelancer or individual in RESICO | CFDI, withholdings, monthly returns and acknowledgments |
| Business with several bank accounts | Reconciliation by account, collections and cash controls |
| Legal entity with employees | Electronic accounting, payroll, taxes and reports for owners |
| Taxpayer with an open SAT matter | Case file, formal response, deadlines and working papers |
What an accounting firm should solve
An accounting firm receives invoices, bank statements, payroll movements and tax notices. Its job is to make those sources agree. The firm should classify income and expenses, review issued and received CFDI, reconcile bank accounts, prepare returns and store each acknowledgment with the calculation behind it.
For an individual, the main issues are often the tax regime, income actually collected, deductions, VAT and the annual return. A legal entity also needs controls for owner transactions, nondeductible expenses, provisional payments, payroll and financial statements.
At month end, you should be able to answer four questions without chasing the accountant. What was filed? What was paid? What is still open? Which document supports each amount? The close is incomplete if the firm did not collect enough information to answer them.
Signs there is a real process
- They ask for your tax status certificate, regime, activities and obligations.
- They compare CFDI with bank activity before calculating tax.
- They deliver acknowledgments, working papers or a monthly summary.
- They warn you about pending items before the deadline.
- They explain differences clearly and document decisions.
- They have a secure way to receive documents and answer questions.
Without a calendar, named owners and evidence, the service runs on memory and last-minute requests. That stops working as soon as transaction volume rises or the business adds employees, partial payments, withholdings or more bank accounts.
How to compare firms beyond price
Price matters. Comparing fees without comparing scope does not. A low monthly fee becomes expensive when the firm files without support or loses acknowledgments. A high fee is no better if it buys more meetings but no reconciliations or working papers.
Ask every firm the same questions and require written answers in the proposal:
| Question | Why it matters |
|---|---|
| What documents do you review each month? | Clarifies whether they validate evidence or only capture data |
| How do you handle canceled CFDI and payment complements? | Prevents gaps between invoices, banks and filings |
| What do you deliver after filing? | Without the acknowledgment, calculation and summary, you cannot reconstruct the close |
| How do you warn about pending obligations? | Compliance needs a calendar, not improvisation |
| What happens if SAT shows differences? | There must be a review and response path |
You can use the Fintax services scope as one reference when comparing deliverables, even if you are considering other firms. A final proposal should separate recurring monthly work from procedures billed on request.
Common hiring mistakes
Asking for "just filings" often leaves the real problem untouched. Submitting a return can take minutes. Rebuilding months without reconciliations, correcting CFDI or proving deductions takes much longer.
Physical proximity is not proof of control. Searching for an "accounting firm near me" makes sense when you need onsite visits or paper records handled locally. For monthly work, secure document exchange, stated response times and a complete close file matter more.
Vague scope is another common mistake. Monthly accounting, payroll, annual returns, SAT procedures, compliance opinions, invoicing, IMSS and INFONAVIT work are not always included. The proposal should separate included work, add-ons and the price for anything outside the plan.
What to review before signing
Gather this information before requesting quotes:
- Download your tax status certificate.
- List your current tax obligations.
- Gather recent filing acknowledgments.
- Identify banks, payment platforms and income sources.
- Confirm whether your e.firma is current.
- Find canceled CFDI, pending payments and complements.
- Note any procedure or SAT difference that remains open.
These details let the firm estimate the actual workload. They also expose a generic price that will later grow through add-on charges.
One closing question before you hire
Ask for a written answer to this question: "What will I receive each month, and how can I verify that the accounting was reviewed?" The answer should name deliverables, dates, open items and owners. "We file your returns" leaves too much undefined.
When to switch accounting firms
Switch firms if you do not receive acknowledgments, cannot trace the tax calculation or send the same records again every month. A slow response to a SAT difference is another clear warning, especially when nobody can produce the calculation or the file submitted.
Growth can force a change even when the former service was adequate. Payroll, imports, owners, large customers or several bank accounts require different controls. Revisit the scope before the business outgrows the firm.
Frequently asked questions
What does an accounting firm do?
It organizes financial and tax records, calculates taxes, files returns, reviews CFDI, reconciles bank accounts and keeps the supporting evidence. Payroll, IMSS and INFONAVIT work may be included, but the contract should say so.
How do I know if an accounting firm is reliable?
It should explain how it closes each month, request the necessary records and deliver acknowledgments with the underlying calculations. It should also work with deadlines and named owners. Results promised before reviewing your data are a warning sign.
Is a remote accounting firm a good option?
Yes, if it uses a secure document channel, reports progress and states response times. Office location does not replace reconciliations, acknowledgments or a reviewed monthly close.
How much does an accounting firm cost?
It depends on the tax regime, CFDI volume, bank accounts, payroll and required filings. A serious quote comes after the firm reviews those facts and separates any additional services.
Official links to complete the task
Open official services from a new browser tab, confirm the taxpayer and period, and save the resulting acknowledgment or evidence with the case.
