Overview
- The IMSS published the new rules that took effect on October 22, 2026, and they apply only to new Modalidad 40 incorporations from that date.
- Under the rule change new applicants can only use their last registered salary plus up to one UMA to calculate contributions, cannot hire coverage retroactively, and must apply through digital channels while existing registrants keep their contracted conditions.
- President Claudia Sheinbaum and IMSS officials said the measures respond to detected frauds and large pension costs that strain the institute's finances.
- Lawyers, unions and opposition parties say the IMSS lacks authority to impose the cap without a law and expect a wave of amparos as Morena studies a legislative route to codify the limits.
- IMSS ordered a six-month financial and legal review by its finance, actuarial and legal units to produce proposals that could lead to formal legislative reform or a change in the administrative rules, and the new limits immediately change retirement plans for workers who had planned to raise their pension base.