Regulatory Context
On July 16th, 2026, Resolution ACDO.AS2.HCT.290626/176.P.DIR of the Technical Council of the Mexican Social Security Institute (IMSS) was published in the Federal Official Gazette. As of July 16th, 2026, the Advanced Electronic Signature (e.firma), whose digital certificate is issued by the Tax Administration Service (SAT), will be the only valid digital certificate for employers and other obligated parties to carry out acts before the IMSS through electronic means, including enrollment filings for hiring, termination, and salary modification.
The Resolution abolishes the Employer Electronic Identification Number (NPIE) and the digital certificate issued by the IMSS itself, and accordingly renders without effect resolutions 43/2004 and 533/2006, published in the Federal Official Gazette on March 3rd, 2004, and March 7th, 2007, respectively, which governed the use of electronic means in the performance of employer obligations. It further provides that the linking of legal representatives, administrators, or equivalent figures acting on behalf of an employer or obligated party, whether an individual or an entity, must be carried out exclusively through the IMSS Virtual Desk (Escritorio Virtual), where both the represented party and its representative must sign jointly, each with their own e.firma.
A transition period of 90 calendar days from the date of publication is granted, expiring in mid-October 2026, to migrate to the exclusive use of the e.firma.
Practical Impact
Employers that currently process their electronic filings before the IMSS with the NPIE will lose that access channel once the transition period ends. The change reaches payroll and human resources departments, external payroll service providers, and corporate groups with multiple employer registrations, all of which will require valid e.firma certificates.
The requirement to link representatives through the Virtual Desk with their own e.firma is particularly relevant for companies whose attorneys-in-fact are foreign individuals without a SAT-issued certificate, as well as for organizations in which filings are handled by third parties under informal arrangements.
Considerations
It is advisable to verify the validity of the e.firma of both the entity and the authorized individuals who carry out filings before the IMSS, renew expired certificates, identify who currently operates with the NPIE, and complete the linking of representatives in the Virtual Desk within the transition period. It may also be necessary to review powers of attorney and internal protocols on social security filings to reflect the new authentication framework.
