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Mexico Social Security Contributions Guide 2026

Mexico's social security system is funded through mandatory contributions to the IMSS (Instituto Mexicano del Seguro Social), INFONAVIT (housing fund), and SAR/AFORE (retirement savings). Employees contribute approximately 2% on a sliding scale based on salary, while employers bear the majority of the burden at roughly 25–30% of payroll. Understanding these obligations is essential for both employers operating in Mexico and employees calculating their total compensation.

Overview — IMSS Contributions

The IMSS is Mexico's comprehensive social security institute covering healthcare, disability, life insurance, daycare, and retirement. Contributions are calculated on a bi-monthly basis using the employee's daily integrated salary (Salario Diario Integrado — SDI), which includes base salary plus benefits and bonuses. The SDI is capped at 25 times the UMA (Unidad de Medida y Actualización), approximately MXN 2,714 per day in 2026. Contributions are split between the employee, employer, and a small government subsidy.

Employee Contributions — ~2% of Salary

Employee contributions to IMSS are deducted directly from payroll. The rate is not a fixed percentage but rather a sliding scale based on the employee's daily salary, divided into salary brackets. For 2026, the employee contribution ranges from approximately 0.9% to 2.2% of the SDI, covering:

  • Sickness and maternity (Enfermedades y Maternidad) — medical care, hospitalization, and maternity benefits. Employee pays ~0.4% of SDI.
  • Disability and life (Invalidez y Vida) — long-term disability and life insurance. Employee pays ~0.6–0.7% depending on salary bracket.
  • Retirement pensions (Cesantía en Edad Avanzada y Vejez) — old-age pension funding. Employee pays ~0.4–0.5%.

Lower-wage employees contribute proportionally less due to the sliding scale design. The employer withholds these contributions and remits them to the IMSS along with the employer's share.

Employer Contributions — ~25–30% of Salary

Employers bear the majority of IMSS contribution costs. Total employer contributions typically range from 25% to 30% of the employee's SDI, broken down as follows:

  • Sickness and maternity — ~9.0–9.5% of SDI (varies by risk classification). Covers medical services, hospitalization, and maternity care for employees and their beneficiaries.
  • Disability and life — ~1.75% of SDI. Funds long-term disability and life insurance benefits.
  • Medical expenses (Gastos Médicos) — ~1.05% of SDI. Covers catastrophic medical expenses and high-cost treatments.
  • Daycare (Guarderías) — 1% of SDI. Funds IMSS daycare centers for working parents.
  • Work risk (Riesgos de Trabajo) — 0.5% to 15% depending on the company's risk classification. Most businesses fall in the 0.5–4% range.
  • Retirement pensions — ~3.15% of SDI (employer portion of retirement contributions).

The exact rates depend on the company's risk classification (clase de riesgo) and the employee's salary bracket. Employers must register with IMSS and submit bi-monthly contribution declarations (CFDI de nómina).

INFONAVIT — 5% Employer Contribution

INFONAVIT (Instituto del Fondo Nacional de la Vivienda para los Trabajadores) is Mexico's national housing fund. Employers must contribute 5% of the employee's SDI to INFONAVIT. This is an employer-only obligation — employees do not contribute to INFONAVIT directly. The funds accumulate in individual housing sub-accounts and can be used by employees for:

  • Home purchase or construction loans (creditos hipotecarios INFONAVIT)
  • Home improvement loans
  • Payment of existing mortgage principal
  • Withdrawal upon retirement (if not used for housing)

The contribution is capped at 10 times the UMA (approximately MXN 3,484 per day in 2026). Contributions are remitted bi-monthly along with IMSS payments through the SUA (Sistema Único de Autodeterminación) portal.

SAR/AFORE — Retirement Savings (2% Employer)

The SAR (Sistema de Ahorro para el Retiro) component, now managed through AFORE (Administradoras de Fondos para el Retiro), requires an employer contribution of 2% of the employee's SDI for retirement savings. This is in addition to the IMSS retirement pension contributions. The breakdown of retirement-related employer contributions is:

  • Retirement pensions (IMSS) — ~3.15% of SDI
  • SAR/AFORE retirement sub-account — 2% of SDI
  • Total employer retirement contribution — approximately 5.15% of SDI

These funds are deposited into the employee's individual AFORE account, which is a defined-contribution pension account managed by a private AFORE administrator of the employee's choice. Employees may also make voluntary contributions (aportaciones voluntarias) to boost their retirement savings.

Salary Integration and SDI Calculation

The Salario Diario Integrado (SDI) is the basis for all social security contributions. It includes the employee's daily base salary plus the daily proportional value of benefits and bonuses, such as:

  • Annual bonus (aguinaldo) — minimum 15 days' salary, prorated daily
  • Profit sharing (PTU — Participación de los Trabajadores en las Utilidades) — up to 10% of company profits
  • Holiday premium (prima vacacional) — 25% of vacation pay
  • Housing allowance, meal vouchers (vales de despensa), and other fringe benefits

The integration factor for the SDI is calculated by adding the daily base salary plus (total annual benefits / 365 days). Most employers use software to compute SDI automatically.

Payment and Reporting Process

Employers must submit and pay all social security contributions bi-monthly (every two months). The process involves:

  • SUA (Sistema Único de Autodeterminación) — SAT/IMSS portal for calculating and filing contribution declarations
  • CFDI de nómina — electronic payroll invoices must be issued for each payment and submitted to the SAT
  • IDSE (IMSS Digital de Servicios Electrónicos) — IMSS portal for employer registration and worker registration
  • Deadline: contributions are due by the 17th of the month following each bi-monthly period

Late payments incur recargos (interest) and multas (fines) from IMSS, which can include penalties of up to 70% of the unpaid amount for intentional non-compliance.

FAQs

Are foreign employees working in Mexico subject to IMSS?

Yes, any employee performing work physically in Mexico must be registered with IMSS, regardless of nationality. Foreign employees are entitled to the same IMSS benefits as Mexican nationals. However, employees covered by a social security totalization agreement (convenio de totalización) with Mexico may be exempt for limited periods.

Can employees opt out of IMSS contributions?

No. IMSS, INFONAVIT, and SAR/AFORE contributions are mandatory by law. Both employees and employers must participate. Opting out or misclassifying workers as independent contractors to avoid contributions is a serious violation carrying significant fines and potential criminal liability.

How are bonuses and profit sharing treated for contribution purposes?

The annual bonus (aguinaldo) is partially exempt from IMSS contributions (up to 30 days of salary). Profit sharing (PTU) is generally not subject to IMSS contributions. Other regular benefits must be integrated into the SDI.

What is the penalty for non-compliance?

Penalties for failing to register employees or failing to pay IMSS contributions include fines ranging from MXN 20,000 to MXN 400,000 per affected worker, plus recargos (interest) and potential criminal prosecution for defraudación fiscal (tax fraud) if intentional.

Disclaimer

This guide provides general information about Mexican social security contributions (IMSS, INFONAVIT, SAR/AFORE) for the 2026 tax year. Contribution rates, UMA values, and regulations are subject to change. The information is based on published IMSS and SAT data and may not reflect individual circumstances. Always consult with a qualified Mexican labor advisor or contador for advice specific to your situation. InvestmentKit does not provide legal or tax advice.