IMSS eliminates the NPIE and establishes e.firma as the sole means of digital authentication

With the aim of strengthening the security of electronic procedures and aligning the digital authentication mechanisms used by federal authorities, the Mexican Social Security Institute (Instituto Mexicano del Seguro Social – IMSS) published Agreement ACDO.AS2.HCT.290626/176.P.DIR on 16 July 2026, establishing the exclusive use of the e.firma issued by the Tax Administration Service (Servicio de Administración Tributaria – SAT) for carrying out electronic procedures before the Institute. 

As background, since 2013 various authentication mechanisms had coexisted, including the Employer Electronic Identification Number (Número Patronal de Identificación Electrónica – NPIE). This agreement completes the transition towards a single digital identification scheme. 

Main changes 

• Exclusive use of the e.firma for carrying out electronic actions before the IMSS. 
• Appointment of representatives exclusively through the Virtual Desk (Escritorio Virtual) and with the joint signature of both the represented party and the representative. 
• Elimination of the NPIE and of digital certificates issued by the IMSS. 
• Repeal of previous agreements related to electronic identification mechanisms. 

Transition period 

A transition period of 90 calendar days is granted, commencing from the publication of the agreement in the Official Gazette of the Federation (Diario Oficial de la Federación), to allow employers or obligated parties to migrate to the exclusive use of the e.firma. Therefore, the deadline to complete this transition will be 14 October 2026. 

Implications for employers 

• Verify the validity of their e.firmas. 
• Update legal representatives and access rights within the Virtual Desk (Escritorio Virtual). 
• Strengthen internal controls for the management of digital certificates. 

In summary, companies should consider 

• Migrating from the NPIE to the e.firma. 
• Updating their electronic representation frameworks. 
• Verifying current access rights, authorities and authorisations. 
• Strengthening controls related to digital identity. 

How can we help? 

• Compliance assessment. 
• Review of legal representation processes. 
• Validation and management of e.firmas. 

At Forvis Mazars, our team of specialists is available to support you in the analysis and implementation of these obligations.