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Tax Defense Against IMSS and INFONAVIT: Contributions and Penalties

6 min read · April 2025

Tax Defense Against IMSS and INFONAVIT: Contributions and Penalties

Mexican Social Security Institute (IMSS) assessment notices and National Workers' Housing Fund (INFONAVIT) fines can be contested. Many employers pay them without review, assuming they are correct. Frequently, they are not.

Why Can Settlement Notices Be Wrong?

IMSS calculates contribution discrepancies based on the information it has on record: reported wages, number of employees, and days of service credited. If the employer has not timely updated enrollment records (registrations, terminations, salary changes), IMSS may determine discrepancies that do not reflect reality.

The Recurso de Inconformidad: Your First Line of Defense

Upon receiving an IMSS settlement notice or penalty, the employer has 15 business days to file a recurso de inconformidad (administrative appeal) with the same authority. The appeal must:

The Administrative Litigation Proceeding

If the administrative appeal is unsuccessful, the next step is administrative litigation before the Federal Court of Administrative Justice. It is a longer process (12 to 24 months) but allows for a broader review of the grounds for the determination. In many cases, simply filing the lawsuit motivates IMSS to reconsider its position.

INFONAVIT: Discrepancies in Employer Contributions

INFONAVIT (National Housing Fund) can also determine discrepancies in employer contributions. The challenge mechanism is similar: a written appeal within 15 days and, if unsuccessful, administrative litigation. Additionally, INFONAVIT has a payment agreement program that may be advantageous when the discrepancy is partially correct.

Representative case

How we work: before and after

Situation based on real cases handled by the firm. Data modified to protect client confidentiality.

Before

Company Facing an IMSS Settlement Notice of $780,000 MXN with Calculation Errors

A service company in SLP received an IMSS assessment notice for $780,000 covering alleged contribution discrepancies over three fiscal years. Upon review, we found that IMSS had calculated contributions based on wages of workers who had already been terminated and whose payroll deregistrations had not been properly processed in the system.

After

Settlement Notice Reduced by 65% Through Administrative Appeal

We filed the challenge with the complete IDSE payroll movements, payroll records for the period, and a worker reconciliation report. IMSS acknowledged errors in 23 of the 31 contested workers. The assessment was reduced to $273,000. The balance was paid in 6 monthly installments.

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