Why Paying the “Correct Salary” Still Leads to IMSS Penalties
Why “We Paid the Right Salary” Is Not a Defense
Many employers believe that as long as employees receive their agreed salary, they are compliant with Mexican labor and social security laws.
IMSS does not evaluate compliance based on what the employee receives — it evaluates compliance based on what is reported, calculated, and contributed. As a result, companies that pay the “correct salary” still frequently face penalties.
This article explains why IMSS penalties occur despite correct salary payments and how employers can avoid this common trap.
How IMSS Defines Compliance
IMSS focuses on the Salary Base for Contributions (SBC), not just take-home pay.
The SBC determines how much employers must contribute for:
- Health insurance
- Disability and life insurance
- Workplace risk insurance
- Retirement and housing
Errors in SBC calculation are among the most common penalty triggers.
Mistake #1: Incorrect SBC Calculation
What Must Be Included in the SBC
IMSS requires employers to include more than base salary, such as:
- Bonuses
- Commissions
- Incentives
- Certain benefits in kind
Excluding variable compensation leads to underreported contributions.
🔗 Internal link: /social-security-contributions-in-mexico-what-foreign-employers-must-pay
Why This Happens Often
Employers may:
- Treat bonuses as discretionary
- Pay commissions irregularly
- Classify benefits incorrectly
IMSS treats these as part of salary unless clearly exempt.
Mistake #2: Paying Correctly but Reporting Late
Timing Matters
Even when salary amounts are correct, IMSS penalties apply if:
- Employee registration is delayed
- Salary changes are reported late
- Contribution payments miss deadlines
Late reporting is treated as non-compliance, regardless of payment accuracy.
Mistake #3: Misclassified Benefits
Certain benefits may be partially exempt, but only if specific conditions are met.
Common errors include:
- Exempting benefits without legal basis
- Lacking supporting documentation
- Applying exemptions inconsistently
IMSS auditors review benefit classifications closely.
Mistake #4: Informal or Offshore Payments
Paying part of compensation:
- In cash
- From abroad
- Outside payroll
does not reduce IMSS obligations. In fact, it increases audit exposure.
🔗 Internal link: /the-hidden-risks-of-paying-employees-in-cash-in-mexico
Mistake #5: Assuming Payroll CFDIs Automatically Match IMSS
SAT and IMSS systems cross-verify payroll data.
Discrepancies between:
- Payroll CFDIs
- IMSS reported salaries
- Bank transfers
trigger automatic reviews.
🔗 Internal link: /how-backdated-payroll-corrections-are-treated-by-sat
Mistake #6: Misunderstanding Variable Pay
Variable compensation must be integrated into the SBC using averaging methods.
Failure to adjust SBC correctly results in:
- Underpayment of contributions
- Retroactive adjustments
- Penalties and surcharges
🔗 Internal link: /how-to-structure-commission-based-pay-for-remote-employees-in-mexico
Mistake #7: Ignoring Employer Risk Classification
IMSS contributions depend on:
- Industry classification
- Workplace risk category
Incorrect classification can trigger audits even when salaries are accurate.
Why IMSS Penalties Are Retroactive
IMSS may assess penalties retroactively for several years, including:
- Contribution differences
- Inflation adjustments
- Surcharges
- Fines
Good faith does not eliminate liability.
Common Employer Assumptions That Fail
- “Employees were paid in full”
- “The amounts were agreed in the contract”
- “We corrected it later”
- “It was an accounting issue”
IMSS evaluates reporting accuracy, not intent.
How to Reduce IMSS Penalty Risk
Audit SBC Calculations Regularly
Ensure all compensation elements are correctly integrated.
Align Payroll and IMSS Reporting
Payroll, CFDIs, and IMSS declarations must match.
Document Benefit Exemptions
Maintain legal justification and evidence for every exemption.
Use Compliant Payroll or EOR Providers
Experienced providers reduce reporting gaps and audit exposure.
🔗 Internal link: /how-eors-in-mexico-handle-social-security-payroll-and-taxes
Conclusion
In Mexico, paying the “correct salary” is only part of compliance. IMSS penalties arise when reporting, classification, or calculation rules are not followed precisely.
Employers who understand how IMSS evaluates compliance — and structure payroll accordingly — can avoid costly penalties, audits, and retroactive assessments.
