# Reimbursing employees from a Mexican RESICO company: step by step

> How to reimburse employees for mileage without it being reclassified as salary under IMSS and ISR.

**Author:** Rodrigo Vázquez — Mexican Tax Specialist (SAT, CFDI)  
**Published:** 2026-05-01  
**Updated:** 2026-05-01  
**URL:** https://quilometragem.com/blog/reimbursing-employees-from-a-mexican-resico-company-step-by-step

**TL;DR:** Flat monthly mileage payments are salary to SAT and IMSS. Real variability, a logbook, and CFDIs are the defense.

- Signed written policy
- Per-trip logbook (GPS preferred)
- Documented MXN 5-8/km rate
- Pay under a separate concept
- Quarterly IMSS exposure review

## The central risk

SAT and IMSS share one doctrine: any periodic fixed payment to a worker is presumed salary. A flat MXN 4,000/month for 'fuel' with no variation and no logbook gets reclassified as salary, triggering ISR + IMSS contributions, surcharges, and penalties. To avoid that, mileage reimbursement must vary with real travel and be backed by a trip log.

## Step 1: written policy

The policy belongs in the Internal Work Regulation (RIT) or as an annex to the individual contract. It must specify eligibility, the per-km rate and how it's updated, eligible vs ineligible trips, the submission deadline (recommend: by end of the following month), and required documentation (logbook + fuel CFDIs).

## Step 2: mandatory logbook

Each trip must record date, origin, destination, specific business purpose, kilometers, and client/project. SAT accepts paper, spreadsheet, or app — what matters is that it exists and is consistent. GPS apps are the most defensible because the number doesn't depend on the employee's memory.

## Step 3: defensible per-km rate

SAT publishes no official rate. The Mexican market in 2026 runs MXN 5-8/km depending on vehicle and region. Document the methodology (fuel + maintenance + depreciation), review quarterly against published fuel prices, and apply the same rate to comparable roles.

## Step 4: payment route

Pay through payroll under a separate code labeled 'Reimbursement – mileage' (never 'bonus' or 'compensation'), or via a separate transfer referencing the period's logbook. Both are valid; payroll is simpler for reconciliation, separate transfers are more visibly non-salary.

## Step 5: CFDI and accounting

The reimbursement is deductible under ISR Law Art. 25 as a necessary expense. Fuel CFDIs paid by the employee must be issued in their name and attached to the logbook. Book the reimbursement to 'travel expenses' or 'selling expenses', not 'wages'.

## Step 6: quarterly IMSS exposure review

Each quarter, compute reimbursement / nominal salary by employee. If the ratio exceeds 30% for anyone, run a specific review: is variability real (40-160% of the period average)? Does the logbook back every peso? Are there zero-km periods (vacation, leave)? IMSS reclassification visits target employees with effectively identical payments for 12 months.

## Errors that trigger penalties

1. Identical fixed monthly payment for more than 6 months.
2. Year-end logbook reconstructed from memory.
3. Missing or third-party-issued fuel CFDIs.
4. Reimbursement >50% of base salary with no documentary justification.
5. Policy not signed or unchanged for 3 years.

## Frequently asked questions

### Can I pay mileage in cash?

Yes, but you lose deductibility if fuel CFDIs and logbook are missing. Transfer or payroll is more defensible.

### How much reimbursement before it counts as salary?

No official percentage. Above 30-40% of base salary, build a thorough documentary justification.

### Can the logbook be in Excel?

Yes, but it carries more SAT-visit risk than a GPS app. App + periodic PDF export is the safer combo.

## Sources

- [Ley del ISR Art. 25 — Deducciones autorizadas](https://www.diputados.gob.mx/LeyesBiblio/pdf/LISR.pdf) — Cámara de Diputados (2026-05-01)
- [Ley del Seguro Social Art. 27 — Salario base de cotización](https://www.diputados.gob.mx/LeyesBiblio/pdf/LSS.pdf) — Cámara de Diputados (2026-05-01)
- [SAT — Guía de llenado del CFDI 4.0](https://www.sat.gob.mx/) — Servicio de Administración Tributaria (2026-05-01)