Executive answer
Mexico’s principal 2026 transfer pricing obligations relating to fiscal year 2025 do not all share one due date. For a calendar-year corporation, the annual income tax return is generally filed within three months after year-end. The Article 76, section X related-party information is due May 15. The Article 76-A local return is also due May 15 for taxpayers within its scope. The master and country-by-country returns are generally due December 31.
Those dates do not mean work can begin in March or May. The amount reported in the annual return should be supported by agreements, accounting and analysis. Anexo 9 and the local return should reconcile to that amount. The master file depends on global information. Country-by-country reporting requires jurisdiction-level data controls. A defensible calendar begins during the fiscal year and assigns internal deadlines before each legal deadline.
This calendar is designed for taxpayers whose fiscal year follows the calendar year. Applicability changes with the entity, tax regime, statutory-audit status, Article 32-H Federal Fiscal Code profile, transactions, amendments to the 2026 Miscellaneous Tax Resolution and enabled filing forms. The first step is not copying dates; it is confirming which deliverables apply to each taxpayer.
What is being reported in 2026
Most milestones in this calendar report information for the year ended December 31, 2025. That distinction prevents files from being named only for the filing year. “2026 Local File” can be read as a file for fiscal year 2026, although the return submitted in May 2026 ordinarily covers 2025 controlled transactions.
Use two fields in every tracker: fiscal year reported and filing date. A clear file name would be “MX Local Return FY2025 — filed 2026.” Apply the same convention to the study, benchmarking analysis, Anexo 9, tax-situation information return, statutory-audit schedules and global files. This simple control reduces period errors.
The 2026 Miscellaneous Tax Resolution was published on December 28, 2025. By this article’s August 2, 2026 cutoff, subsequent amendments and annexes had been issued. Teams should therefore check the version and transitional provisions in force when a filing is made. A headline announcing an amendment does not prove that a transfer pricing requirement changed; the relevant rule, annex or procedure must be located.
Before March 31: close and annual income tax return
Article 76, section V, requires corporations to file their annual return within three months following fiscal year-end. For a 2025 calendar year, the ordinary milestone is March 31, 2026. Before that date, the company should decide whether controlled dealings produced an arm’s length result and whether an adjustment is needed.
The internal process should begin in January with a preliminary trial balance and updated transaction inventory. During February, agreements, functional analysis and comparable information are validated; the result is calculated; and any adjustment is communicated to accounting with time to review income tax, VAT, electronic invoicing and customs effects. March should close the reconciliation among the trial balance, workpapers and annual return.
Filing the annual return before completing the analysis creates three risks. A later study may produce a different amount. A true-up may be documented after the fact without coherent accounting. And the May returns may repeat a number that cannot be traced. If the full file cannot be completed, there should at least be a controlled estimate, documented assumptions and a completion plan.
Article 76 also contains a February 15 information requirement for financing granted or guaranteed by foreign residents. Although this is not “the study,” it belongs in the intercompany financing calendar and should align to balances, currency, interest rate and maturity data.
May 15: transaction information and local return
Article 76, section X, requires the requested information on related-party transactions to be filed by May 15 of the following year through the approved official form. The SAT portal lists Anexo 9 of the Multiple Information Return as the annex for related-party transactions. The current form and instructions should be reviewed at filing; prior-year software or worksheets should not be reused without checking the fields.
The Article 76-A local information return is due on the same May 15 date for taxpayers within scope. A shared deadline does not make the two returns identical. Anexo 9 organizes transactions and the data requested by its form. The local return explains organization, business, controlled dealings, financial information and comparables. Both should agree with the supporting file and accounting records, but scope and filing population must be tested separately.
Preparation should continue after the annual return instead of restarting. April is used to freeze the transaction table, assign method and result, reconcile amounts by counterparty and transaction type, and document differences against the study. For the local return, validate that the functional narrative agrees with agreements and the master file, that financial statements belong to the filing taxpayer, and that comparable-company figures are reproducible.
The 2021 reform moved the local return deadline to May 15. Older secondary materials that state December 31 for all Article 76-A filings may be outdated. The current statutory text should control.
ISSIF and SIPRED: overlapping workstreams
Taxpayers filing Mexico’s tax-situation information return or a statutory tax report may face transfer pricing sections and questionnaires. The date and format depend on the taxpayer’s facts, the relevant return or report, and current annexes. Assigning one universal date to every company without checking its status is unsafe.
Operationally, ISSIF and SIPRED belong in the same calendar because they reuse study conclusions and can expose discrepancies. Assign every question to a source: trial balance, annual return, Anexo 9, local return, agreement or technical memorandum. Each answer should trace to both an amount and a conclusion. PT-010 and PT-011 address those workstreams separately.
December 31: master and country-by-country returns
Article 76-A provides that the master and country-by-country information returns are due by December 31 of the year following the reported fiscal year. For FY2025, the ordinary milestone is December 31, 2026. It should not be confused with the May local return.
The master file is often coordinated by the parent group, but the Mexican entity should test consistency. Descriptions of the business, intangibles, financing and global tax position can contradict the local narrative when offices work independently. The plan needs one date to receive the draft, another for Mexico review and another to resolve differences.
Country-by-country reporting applies only when statutory conditions are met. When it applies, controls should begin long before December: entity and jurisdiction classification, related and unrelated revenue, tax, capital, accumulated earnings, employees, assets and activities. Filing the return cannot repair classification problems embedded in the consolidation process.
2026 operating calendar
| Internal period | Legal or operational milestone | Deliverable | Critical dependencies |
|---|---|---|---|
| January | Reconstruct FY2025 | Inventory and preliminary trial balance | Counterparties, agreements, accounts, true-ups |
| February 15 | Foreign financing information, where applicable | Article 76 section VI data | Balances, currency, rate, beneficial recipient, maturity |
| February–March | Arm’s length test | Study or preliminary analysis | Functional profile, comparables, segmentation |
| March 31 | Ordinary calendar-year corporate return | Annual income tax return and determined adjustment | Accounting close and management decision |
| April | Information reconciliation | Ledger-study-forms bridge | Frozen transaction table |
| May 15 | Section X information | Anexo 9/applicable form | Amounts by party, type, method and result |
| May 15 | Local return, if Article 76-A applies | FY2025 local return | Study, financials, comparables and narrative |
| May–September | ISSIF/SIPRED depending on facts | Questionnaires and schedules | Taxpayer-specific calendar and traceable sources |
| August–November | Global-local review | Master and CbCR drafts | Group data and Mexico comments |
| December 31 | Master and CbCR where applicable | FY2025 information returns | Approval, translation and global controls |
Zugzwang’s Calendar Readiness service converts these milestones into an entity-level calendar with owners, dependencies, status and reconciliations. The objective is to identify in August what should not be discovered on a filing day.
Controls that belong with every date
Every deliverable needs version control, a preparer, reviewer, data-freeze date and named source. Maintain a stable transaction identifier. If a reclassification occurs after the annual return, record its effect in every dependent file. Avoid letting each return maintain an independent spreadsheet without a bridge.
Use a RACI by data type: accounting owns balances; legal owns agreements; operations validates functions; treasury owns financing; tax determines applicability; and the parent provides global information. An adviser can prepare analysis, but the company must approve facts and amounts.
Common errors
The first is treating May 15 as the project start. The second is preparing the local return and Anexo 9 from different datasets. The third is using December 31 for every Article 76-A filing. Companies also maintain a single “Mexico” calendar without separating entities, even though only some fall within Article 76-A, ISSIF or statutory audit requirements.
Another mistake is assuming that the resolution published in December remains unchanged all year. Verification should cover the original resolution, amendments, annexes and procedure sheets. Finally, an on-time filing does not cure inconsistent data. The receipt proves submission, not the quality of the file.
Recommended actions for the remainder of 2026
At this article’s cutoff, the ordinary March and May milestones have passed. Review receipts, the actual files submitted and their reconciliations. If omissions or differences exist, assess correction routes and connected consequences before the next filing. Do not amend one return without evaluating its effect on the others.
For December, confirm now whether the master and country-by-country returns apply, who will provide the global file and which Mexico information is required. In parallel, open the FY2026 transaction inventory so that the 2027 close does not repeat a reactive process.
Related topics
- PT-005: defensible documentation file.
- PT-006: Anexo 9.
- PT-007: local return.
- PT-008 and PT-009: master file and CbCR.
- PT-010 and PT-011: ISSIF and SIPRED.
Sources and verification date
- Mexican Income Tax Law, current text, Articles 76 and 76-A.
- 2026 Miscellaneous Tax Resolution, published December 28, 2025.
- SAT Multiple Information Return portal.
- OECD Mexico Transfer Pricing Country Profile.
Sources checked on August 2, 2026. Confirm the taxpayer’s regime, fiscal year, amendments and enabled form before filing; this guide is not an individualized compliance calendar.
If you need to close March and May differences or prepare for December, request an entity-level reconciliation connecting receipts, amounts, supporting files and owners.