# Mexico IMSS Modalidad 40 pension scheme reforms

> Live situation record from CLSTR: https://clstr.news/situations/mexico-imss-modalidad-40-pension-scheme-reforms
> Updated: 2026-10-26T01:59:32.000Z. Sources: 57. Developments: 3.

The Mexican Social Security Institute (IMSS) has introduced new regulations for Modalidad 40, a voluntary contribution scheme designed to help workers increase their pension amounts. The administration stated the adjustments aim to prevent fraud and the misuse of public resources, following irregular practices that reportedly resulted in losses estimated in the hundreds of billions of pesos.

Under the new rules, effective October 22, 2026, new applicants must base their contributions on their last registered salary, with a potential increase of up to one Unidad de Medida y Actualización (UMA). This replaces previous practices where eligible workers could choose a contribution salary of up to 25 UMA. Additionally, the reforms eliminate retroactive incorporations, meaning insurance coverage begins only from the date an application is submitted, and all new procedures must be completed digitally.

These changes are not retroactive; individuals already enrolled in the scheme or currently receiving pensions will maintain their existing conditions. While business organizations have expressed support for the measures to strengthen transparency, the decision has faced immediate backlash from labor organizations and legal experts. The Federation of Labor Groups of the Mexican Republic (FAO) has announced plans to initiate legal action, arguing that the administrative agreement violates fundamental rights and exceeds the authority of the IMSS Technical Council. Legal experts and academics have noted that Article 218 of the Social Security Law allows for contributions at a higher salary than the last registered, suggesting that an administrative agreement cannot override federal law and may contravene the principle of human rights progressivity. Some legal specialists have further warned that affected workers may encounter difficulties seeking judicial relief through amparos due to the current state of the Mexican judiciary.

## Claims

- The IMSS Technical Council agreement was published on October 21, 2026. (corroborated by 6 sources)
- New contribution bases are limited to the last registered salary plus a maximum of one UMA. (corroborated by 6 sources)
- The new rules eliminate the possibility of retroactive contributions. (corroborated by 3 sources)
- Existing participants under Modalidad 40 will maintain their current conditions until their contract ends. (corroborated by 2 sources)
- There were approximately 275,000 people enrolled in Modalidad 40 at the end of 2024. (corroborated by 2 sources)
- Legal specialists warn that amparos against the changes might be dismissed by the new judicial system. (corroborated by 2 sources)
- New Modalidad 40 procedures must be conducted through digital means. (corroborated by 2 sources)
- Legal experts suggest the changes may violate the principle of progressivity of human rights. (single source)
- The IMSS claims the changes aim to prevent labor simulation practices. (single source)
- The IMSS collected more than 27 billion pesos through Modalidad 40 in 2024. (single source)

## Timeline

### 2026-10-26: IMSS Modalidad 40 registrations triple amid government review

Registrations in Mexico's IMSS 'Modalidad 40' have tripled since 2013, prompting a government review due to fraud concerns and pension inflation.

3 sources. https://clstr.news/cluster/imss-modalidad-40-registrations-triple-amid-government-review

### 2026-10-24: IMSS modifies Modalidad 40 rules for voluntary pension contributions

IMSS has updated Modalidad 40 rules, limiting new voluntary contributions to the last registered salary plus one UMA, restricting workers' ability to increase future pension amounts.

19 sources. https://clstr.news/cluster/mexico-modifies-imss-modalidad-40-pension-rules

### 2026-10-21: IMSS modifies Modalidad 40 pension scheme to combat fraud

Mexico's IMSS has updated its Modalidad 40 pension scheme to prevent fraud. The changes limit new applicants to their last registered salary plus one UMA, though existing participants are protected.

42 sources. https://clstr.news/cluster/mexico-president-demands-ine-transparency-amid-supplier-investigation

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Cite as: Mexico IMSS Modalidad 40 pension scheme reforms. CLSTR, https://clstr.news/situations/mexico-imss-modalidad-40-pension-scheme-reforms