Mexico's IMSS mandates SAT e‑firma for all employer digital filings

IMSS e. firma NPIE digital authentication 90‑day transition

The Mexican Institute of Social Security (IMSS) approved a reform that makes the Advanced Electronic Signature (e. firma) issued by the Tax Administration Service (SAT) the sole digital certificate for employers and obligated parties. The change, endorsed unanimously by the IMSS Technical Council and published in the Official Gazette, replaces the longstanding Number Patronal de Identificación Electrónica (NPIE).

Employers have a 90‑day transition period starting on 16 July to migrate to the e. firma for all electronic affiliation and other procedures. The institute will provide guidance through its Virtual Desk and contact centers. The reform is expected to simplify paperwork, strengthen legal certainty, curb identity‑theft and fraudulent filings, and improve transparency. Particular emphasis is placed on Quintana Roo, where tourism accounts for a large share of formal employment, to accelerate administrative processes for hotels and service providers.

The measure does not create new obligations beyond the authentication method, but it grants the e. firma the same legal weight as a handwritten signature.