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Tax checklist for Mexican SMEs 2025 - List of SAT obligations with checkmarks to avoid penalties

Tax checklist for SMEs in 2025: what your accounting system can't do without

The 2025 tax checklist your accounting system can't ignore: invoices, entries, reconciliation and filings, with no gaps.

Reading time

4 minutes

Written by

Alberto Amoretti

Published

September 17, 2025

The cost of not having a complete accounting system

A SAT penalty for non-compliance can cost anywhere from $1,920 to $38,350 pesos. An error in a filing can generate surcharges of 20% on the omitted tax. For an SME, these mistakes are not just costly; they can be fatal to cash flow.

This checklist will help you avoid those mistakes and ensure that your accounting system complies with all the tax obligations of 2025.

Issued and received invoices (SAT)

Issued invoices:

  • All invoices must be stamped with a valid CSD
  • Complete tax information: RFC, tax address, tax regime
  • Detailed line items with the SAT product/service code
  • Withholdings and taxes calculated correctly
  • Addenda for corporate clients when they require it
  • Timely cancellation of incorrect invoices (72 hours maximum)

Received invoices:

  • Complete monthly download from the SAT portal
  • Validation that the invoices are in your name and RFC
  • Verification that suppliers exist in the SAT validation list
  • A file organized by month and supplier
  • Digital backups accessible for a minimum of 5 years

How to automate?: Tools like Tablia automatically download all your SAT invoices every night and validate their tax information.

Automatic accounting entries

Mandatory requirements:

  • Each invoice must generate its corresponding accounting entry
  • Correct classification according to your chart of accounts
  • Cost centers assigned for management control
  • Supporting documentation linked to each entry
  • A chronological sequence with no gaps or duplicates
  • Digital signatures on entries for audits

Common mistakes you should avoid:

  • Creating entries days or weeks after receiving invoices
  • Using generic accounts that don’t reflect the reality of the expense
  • Failing to back up entries with supporting documentation
  • Allowing unbalanced entries (debit vs credit)

How to automate?: Modern systems create entries automatically as they process each invoice, applying predefined accounting rules.

Monthly bank reconciliation

Mandatory monthly process:

  • Download of bank statements
  • Matching each movement with its corresponding invoice
  • Identification of items in transit
  • Adjustments for differences in dates or amounts
  • Documentation of movements without a tax receipt
  • A signed and dated reconciliation report

Warning signs:

  • Bank movements without a supporting invoice for more than 30 days
  • Recurring differences with the same supplier
  • Deposits with no identified origin
  • Transfers without documentation

How to automate?: Automatic reconciliation matches bank movements with invoices using multiple criteria: amount, date, supplier RFC.

Monthly filings vs annual filings

Monthly obligations:

  • IVA filing (before the 17th of the following month)
  • ISR withholdings on salaries (before the 17th)
  • Informative declaration of operations with third parties (DIOT)
  • Remittance of taxes withheld from third parties

Annual filing:

  • Audited financial statements (if applicable)
  • Annual corporate ISR filing
  • Reconciliation between the accounting records and the filing
  • Supporting documentation for the deductions applied

How to automate?: Systems can generate pre-filings based on the accounting information processed throughout the year.

Key deadlines you can’t forget

January 2025:

  • 2024 annual filing (legal entities by March 31)
  • Update of RFC data
  • CSD renewal if it expires in 2025

February 2025:

  • Annual filing for individuals (by April 30)
  • Submission of audited financial statements

March 2025:

  • Annual informative declaration
  • Certificates of income and withholdings for employees

April-December:

  • Monthly filings before the 17th of each month
  • Monthly DIOT
  • Quarterly provisional payments

How to automate?: Set up automatic alerts for each deadline, with reminders 30, 15 and 3 days in advance.

How to automate everything with Tablia

Complete integration:

  • Automatic SAT downloads
  • Smart invoice processing
  • Automatic generation of accounting entries
  • Automated bank reconciliation
  • Tax deadline alerts
  • Real-time reports

Compliance dashboard:

  • Current status of all tax obligations
  • Alerts for pending documents
  • Progress of monthly filings
  • Tax health indicators

Audit readiness:

  • All documentation digitized and organized
  • Complete traceability of every process
  • Instant compliance reports
  • Secure backups in the cloud

The peace of mind of always being up to date

With this checklist implemented and automated, you can sleep soundly knowing that your company complies with all its tax obligations. No more surprises from the SAT, no more avoidable penalties, no more sleepless nights wondering whether you forgot something important.

Automation isn’t just efficiency; it’s peace of mind and guaranteed compliance.

Automate your accounting with Tablia

Connect the SAT, reconcile your transactions and issue invoices without manual data entry. Less busywork, more control.

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