Your payroll reports to four authorities that cross-check each other on their own: how to shield it (SAT, IMSS, Infonavit and ISN)

Payroll is the only process in your company that reports simultaneously to four authorities — SAT, IMSS, INFONAVIT and the state treasury — which cross-check their bases against each other. One error doesn't create one problem: it creates four. And now that the payroll CFDI feeds the SAT's systems in real time, inconsistencies are no longer uncovered in an audit — they surface on their own.

The four fronts of a clean payroll

Tax (SAT): every payment stamped as a payroll CFDI, ISR withholdings calculated and remitted — stamping without remitting is the first of the cardinal tax sins —, and full consistency between what's stamped, what's declared and what's deducted in the annual return. Payroll that isn't stamped correctly, moreover, is non-deductible (art. 27 and 99 LISR): the formal error becomes a direct 30% cost.

Social security (IMSS): a well-integrated contribution base salary (SBC) — with all the items that integrate it under art. 27 LSS, including the bonuses and commissions that many leave out —, registrations and terminations filed on time, and variables reported every two months. The IMSS also cross-checks against the SAT's CFDIs: the worker stamped at MXN 30,000 and contributing on $10,000 is a differences assessment waiting for a date.

INFONAVIT: the same bases, the same consequences, plus the housing-loan deductions applied and remitted correctly — an omission that creates direct liability for the employer.

State (ISN): your state's payroll tax (in Nuevo León, on remuneration disbursements under the state law in force), with its own base, its own return and its own reviews — the front out-of-state companies forget when they open a local operation.

The schemes that no longer exist (and are still being sold)

There are still firms offering "payroll efficiencies": outsourcing without substance, mass salary-assimilated payments (asimilados a salarios) for operational staff, payments through unions or cooperatives, cash off the books. The 2021 subcontracting reform, art. 15-D of the CFF and the crackdown on simulated payroll invoicing turned all of that into criminal risk, not tax risk. Labeled without ambiguity: red zone — today's savings are the day after tomorrow's tax assessment with joint-and-several liability (and sometimes a criminal complaint). Legitimate payroll efficiency exists, but it lives elsewhere: well-structured and capped social-welfare benefits under the LISR, properly documented benefit plans, and precise salary integration — well-tended legal cents instead of illegal percentages.

Signs that your payroll needs a review now

Recurring differences between what your accountant declares and what your system stamps; workers who "don't show up" at the IMSS but do on the CFDI (or vice versa); bonuses and commissions paid without stamping; salary-assimilated payments that are really employees; and the quietest one: no one in your company can tell you, today, whether your staff's SBC is well integrated. Any one of these is enough to audit the entire process. And if you're about to hire, budget with the real cost — employer contributions, ISN and provisions — using the total cost of an employee calculator: a good share of the bad schemes are sold to employers who found out too late what formal payroll costs.