SAT Wins More Court Battles and Raises the Fiscal Stakes: 80% of the Money at Issue Ended Up with the Treasury in 2025
Mexico’s tax authority strengthened its edge in court, while new rules for challenging tax assessments could make taxpayer defenses even tougher.
The balance in Mexico’s tax justice system has tipped more clearly in favor of the government. By the end of 2025, the Tax Administration Service (SAT) won 55.5% of cases at the final stage and managed to collect 80% of the funds in dispute—nearly 200 billion pesos—according to data from the Ministry of Finance and Public Credit (SHCP). By contrast, taxpayers obtained favorable rulings in 32.9% of cases and recovered 17.4% of the contested amount.
The shift looks significant compared with 2018, when the government won 48.5% of definitive proceedings and kept 73.8% of the money at stake. Beyond the share of rulings, the economic return per lawsuit also rose: Finance reports that, on average, the authority collected 12.8 million pesos for each case it won in 2018, versus 23.5 million in 2025—an increase of 45.5%.
Behind these results is a public policy shift that began during Andrés Manuel López Obrador’s six-year term and continued at the start of Claudia Sheinbaum’s administration: an end to broad-based tax forgiveness, more intensive audits of prior tax years, and a “collection through litigation” strategy in which the SAT not only issues assessments but also mounts stronger defenses in court. In high-profile cases—including tax debts owed by major business groups—court criteria have tended to favor the state’s revenue-collection position.
The authority has also sharpened its technical capabilities. Since 2019, the SAT’s Master Plan has pushed greater use of data analytics, information matching, and digital tools to better target audits. This is happening in an environment where revenue collection has become central to sustaining social programs, increasing public investment in priority projects, and addressing structural spending pressures such as the financial cost of debt and growing needs in pensions and healthcare.
From a macroeconomic standpoint, tighter tax enforcement fits within a broader stability agenda: Mexico has sought to maintain fiscal discipline and credibility with investors, especially in a cycle of moderate growth, where private investment competes with regulatory uncertainty and the economy depends on a close relationship with the United States, its main export destination and a key source of remittances.
2026 Reform: Challenging Assessments Will Be More Expensive and Could Change Companies’ Calculus
One of the most consequential forward-looking changes is the reform taking effect in 2026 to the Federal Tax Code: when the SAT determines a tax assessment, the taxpayer will effectively have two main paths—pay or challenge—but to challenge it, they will have to deposit the assessed amount using a deposit certificate at Banco del Bienestar. The redesign eliminates alternatives that traditionally served as guarantees (for example, arrangements equivalent to surety bonds or letters of credit), raising the financial cost of mounting a defense and restricting liquidity—especially for companies with tight margins or long cash cycles.
At the corporate level, this could translate into more early settlements, greater efforts to “harden” compliance, and increased demand for preventive tax advisory services. For small and mid-sized businesses, the risk is that the new mechanism discourages challenges even when there is a legitimate technical dispute, due to the inability to tie up capital. At the sector level, industries that are intensive in working capital—trade, manufacturing, and logistics—would be particularly sensitive.
The government, for its part, argues that the goal is to strengthen the fight against tax evasion, avoidance, and sham transactions, including the use of fraudulent invoicing. In a country where informality still accounts for a large share of employment and where the base of formal taxpayers is relatively narrow compared with the size of the economy, the authority has sought to focus on large taxpayers and networks of irregular operations to improve collection efficiency without raising broad-based rates.
Even so, specialists warn that the institutional context matters: the perception of reduced judicial independence or pressure to rule in favor of the tax authority can change taxpayers’ expectations of success. If litigation is increasingly seen as a less viable path, the system could shift toward a more revenue-driven design—but with the risk of increasing disputes and discouraging investment if legal certainty weakens.
The potential revenue at issue remains substantial. By the end of 2025, Finance counted 203,221 disputed tax assessments—subject to legal challenges that suspend collection actions—totaling more than two trillion pesos. In a context of public financing needs and pressure to keep the deficit under control, the outcome of these disputes will matter for the flow of tax revenue and for private-sector expectations.
In perspective, the trend points to a more sophisticated SAT with greater capacity to sustain complex cases, while taxpayers face a higher bar to litigate. The key heading into 2026 will be balancing effective enforcement with due process rules and certainty, so that stronger revenue collection does not translate into an added cost for investment and formalization.
