Tax authority audits have changed considerably in recent years. Today, the SAT (Mexican Tax Administration Service) audits taxpayers using artificial intelligence, massive data cross-referencing, and automated systems capable of detecting inconsistencies almost in real time. This means that errors that previously went completely unnoticed can now result in an audit, a fine, or even tax assessments.
At GGAF, we help individuals and businesses prevent risks before they become legal problems. If you've already received a notice, or simply want to strengthen your compliance with your obligations before the authorities audit you, our specialized team of accounting and tax advisors can provide preventative advice and legal representation to protect your assets.
What is the SAT currently reviewing?
The Tax Administration Service 's auditing powers have been strengthened thanks to the automated analysis of information from tax returns, CFDI (electronic invoices), financial institutions, and other authorities. Therefore, it is essential to maintain organized accounting records and have sufficient evidence to support every transaction you make.
1. Materiality of the operations
One of the most closely monitored aspects is verifying that the transactions actually took place. An invoice alone is not enough; the authorities can request contracts, deliverables, emails, photographs, proof of payment, and any other evidence that demonstrates the service was indeed provided or the goods were actually delivered.
When a supplier does not have the infrastructure, staff, or capacity to carry out the operations it invoices, it is very likely that those deductions will end up being rejected.
2. Fake companies and payroll schemes
The SAT maintains constant surveillance over companies that issue receipts without carrying out real activities, as well as over the schemes used to evade taxes or social security contributions through labor simulation.
Therefore, before hiring a supplier, it is advisable to check their tax status and confirm that they do not appear on the lists published by the authorities.
3. Tax discrepancy
Another common contingency occurs when a taxpayer's expenses, investments, or bank transactions exceed the income they declared.
Bank deposits, transfers, card payments, and even transactions between family members can be subject to review if there is no documentation justifying the origin of the funds. The authorities monitor these types of inconsistencies precisely through automated data cross-checking.
4. Errors in CFDI and payroll
Inconsistencies in digital tax receipts, especially in the CFDI payroll version 4.0, continue to be a frequent cause of fines and audits.
Errors in product codes, cancellations that should not have been made, or incorrectly captured information can generate observations that affect both companies and their employees.
5. Foreign trade
Companies that import or export are also under increased scrutiny. Authorities review customs declarations, the origin of goods, temporary imports, and ensure compliance with all customs obligations.
Having incomplete documentation can result in significant penalties.
Related article: Income tax and VAT refunds: stricter criteria from the SAT in 2026
Prevention remains the best strategy
Beyond understanding how the tax authorities operate, what truly makes the difference is having internal controls in place to mitigate risks from the outset. Keeping your accounting up-to-date, maintaining records of every transaction, regularly reviewing your suppliers, and promptly addressing any requirements can prevent costly problems for both individuals and businesses.
GGAF can help you prevent and address tax contingencies
If you've received an audit, a request for information, or simply want to strengthen your compliance before any problems arise, at GGAF we have specialized tax attorneys who can guide you through the entire process. We analyze your company's risks, design preventative strategies, and defend your rights before the authorities when necessary.
Contact us at (81) 4174-5411 and receive legal advice to protect your assets and the stability of your business.
This article is for informational purposes only and does not constitute specific tax advice. For specific situations, consult a certified public accountant.
Frequently asked questions about SAT tax audits
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In some cases, you'll find out because the SAT (Mexican Tax Administration Service) sends notices or initiates audits through your Tax Mailbox. But the reality is that the tax authority detects many inconsistencies automatically by cross-referencing tax returns, CFDI (electronic invoices), bank deposits, and other available information. That's why it's a good idea to get into the habit of checking your Tax Mailbox regularly and keeping your tax information up to date to avoid any surprises.
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If you can't prove that a service was actually provided or that goods were truly delivered, the Mexican Tax Administration Service (SAT) has the authority to reject that deduction and determine tax discrepancies, in addition to any applicable fines. That's why it's so important to keep contracts, documentary evidence, payment receipts, and deliverables: these are precisely what proves the transaction took place and wasn't just a paper invoice.
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Before finalizing any major transactions, it's worth checking that your supplier doesn't appear on the official lists published by the SAT (Mexican Tax Administration Service) regarding companies suspected of engaging in fraudulent activities. It's also a good idea to verify that the supplier actually has the infrastructure, personnel, and capacity to provide the services or deliver the goods they are invoicing.
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No, not necessarily. The issue becomes more complicated when those deposits or financial transactions don't match the income you declared; in that case, the tax authorities will likely ask you to explain their origin. Having documentation on hand to support loans, donations, contributions, or any other transaction helps you avoid unnecessary tax problems.
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The wisest course of action is to respond to the request within the specified deadlines and, from the outset, seek specialized legal advice. A sound preventative strategy, coupled with a well-thought-out response, can reduce risks, avoid preventable penalties, and protect your rights as a taxpayer throughout the entire process.
