Executive answer
The 6.9% base under Article 182 is not the Mexican balance sheet’s total assets. It includes total assets used in the maquila operation during the year, whether owned by the Mexican resident, the foreign resident or any related party, including assets granted for use. The computation requires owner, location, use, period, asset type, currency and method.
The largest gap is often outside Mexican accounting: inventory, machinery, molds and equipment of the foreign principal. The maquiladora should obtain owner records, reconcile them with customs, Anexo 24, maintenance and the plant floor, and apply Article 182 rules for averages, remaining value, months and conversion.
A correct figure needs a traceable master inventory and reconciliation across four universes: Mexican accounting, foreign accounting, customs and physical operations. None is sufficient alone.
Minimum universe
| Category | Possible owner | Key data |
|---|---|---|
| cash and accounts connected with maquila | Mexico | use and applicable procedure |
| raw-material inventory | foreign/related | monthly averages and owner value |
| work in process and finished goods | foreign/related | raw-material component under the rule |
| machinery and equipment | Mexican/foreign/related | acquisition, value, months, use |
| molds, dies and tools | multiple | serial, owner, location |
| leased asset | Mexican related/foreign unrelated | exclusion conditions |
| deferred expenses and charges | Mexico | option and connection |
| shared asset | multiple | authorized proportion where required |
Map each category to the current provision and workpaper.
Build the asset master
Use a stable ID and include description, serial, legal owner, relationship, country, acquisition date and cost, currency, customs entry, location, cost center, start/end date, use percentage, method, Safe Harbor value and support.
Integrate fixed-asset files, Anexo 24, ERP, maintenance, insurance, leases, memorandum accounts and foreign inventory. Search for duplicate serials, unknown owners, zero values, in-transit assets and retired records still on the floor.
Freeze a year-end snapshot and retain monthly changes. Do not overwrite owner or date. Maintain a log showing reason, source, author and reviewer.
Foreign inventory
Article 182 calculates raw material, work-in-process and finished-goods inventory value by summing monthly averages and dividing by months in the year. Each monthly average is opening plus closing inventory divided by two.
Values use the owner’s accounting at import under the standards specified for its residence. For work in process and finished goods processed in Mexico, only raw-material value is considered under the rule. The Mexican ERP should not add local conversion without analysis.
Prepare a workpaper by owner, currency and type. Reconcile units to Anexo 24 and value to the foreign ledger. Investigate freight, overhead, obsolescence, reserves and standard-cost differences. Document owner policy.
For dollar amounts apply the DOF exchange rate prescribed for the last day of the month; for other currencies follow the statutory conversion. Archive tables used. Do not use a generic annual average.
Foreign fixed assets
Article 182 begins with the foreign owner’s acquisition amount and computes remaining value using its statutory method, maximum percentages, months and dates. It prorates the first and last years of use and provides that value cannot fall below the stated 10% acquisition-cost floor.
Obtain original invoice, date, currency, tax class, applicable percentage, in-service date and transfers. Do not use foreign net book value without a bridge; foreign depreciation may differ. Customs value is not an automatic substitute.
Convert using the date and mechanism in the article. Test current-year acquisitions, fully depreciated accounting assets, old, used and moved equipment. The floor may preserve value where the ledger shows zero.
Mexican-owned assets
The Mexican resident’s assets follow procedures established in general rules. Reconcile fixed assets, owned inventory, applicable accounts and tax deduction. Identify items used in maquila versus other activities.
A plant providing additional services needs segmentation. Use cost center, location, hours or capacity with support. Where proportional use requires authorization, do not apply a convenient percentage unilaterally. Retain application and resolution.
Review construction in progress, advances, idle equipment and sold assets. Accounting capitalization date may differ from use.
Leases and exclusions
The article provides an exclusion for certain property leased from Mexican related parties or foreign unrelated parties when conditions are met, including ownership history and arm’s-length disposal under the specified case. Read the full rule before excluding.
Prepare agreement, owner, title chain, relationship, rent, benchmark, use and payments. A third-party lessor’s equipment may previously have belonged to the foreign principal or an affiliate; investigate.
Exclusion from the base does not mean omission from the inventory. Record the asset and legal reason so the reviewer sees the full universe.
Zugzwang’s Asset Base Review integrates Mexican and foreign assets, inventory, FX, ownership and use in a reproducible workpaper.
Full or partial use
Article 182 treats assets located in Mexico and used wholly or partly in the operation as used. Considering only a proportion requires the authorization stated in the text. Identify shared assets and the legal basis before prorating.
Square meters may fit a building; machine hours may fit equipment; transactions may fit a server. The driver should reflect use and be verifiable. Retain source data and sensitivity.
Idle assets do not automatically disappear. Determine whether they are available, under maintenance, backup capacity or abandoned. Document retirement decision and physical date.
Ownership and title chain
Request annual confirmation from each owner showing ID, cost, currency, date, percentage and status. Validate with invoice and agreements. For affiliate transfers retain purchase agreements and arm’s-length support.
Trace whether an asset was owned by a related Mexican enterprise, which can matter under Article 181 and exclusions. A change of foreign entity without physical movement may alter records and the maquila agreement.
Use a conflict matrix: Anexo 24 owner, insurance owner, fixed-asset owner and contractual owner. Close every difference.
Physical and customs reconciliation
Select a sample by value, age, owner and exception. Walk the plant, capture serial and location and compare maintenance. Include small high-value molds and customer property.
Reconcile customs entries, virtual transfers, returns, regime changes and disposals. An asset physically present but discharged in the system requires investigation. Customs and tax should share the same ID.
Document property temporarily outside for repair or loan and in-transit assets at year-end. Analyze location and use under the text rather than logistics cutoff alone.
Illustrative case
Mexican accounting reports MXN 500 million in assets. The foreign principal reports MXN 900 million in machinery and MXN 300 million average inventory. The company initially applies 6.9% to MXN 1.7 billion.
Review finds MXN 80 million of foreign machinery removed in October, MXN 40 million of potentially excludable leased assets, finished inventory containing MXN 25 million of local conversion and Mexican equipment used in another activity. Each item follows a different rule; they cannot all simply be subtracted.
After applying months, ownership, valuation and authorization, the documented base emerges. The example illustrates why preliminary totals are not conclusions.
Control workpaper
Include source value, method adjustment, FX, average, months, floor, proportion, exclusion and final value columns. Every adjustment has a code and note. Reconcile totals by owner and category.
Add checks for complete monthly inventory, missing currency, negative value, floor, dates, duplicates, owner mismatch, missing customs entry and physical-accounting difference. Preparer and reviewer sign.
Connect final value to Result A and the 6.5% comparison. Archive the version used in annual return and DIEMSE.
Monthly governance
Plant reports additions, moves and disposals; customs reports entries; accounting reports Mexican fixed assets; the principal reports foreign fixed assets and inventory; tax owns rules and calculation. Set a practical monthly deadline.
Use alerts for a new owner, asset without invoice, inventory without close, missing FX, product change and shared asset. Year-end should not be the first reconciliation.
Quarterly confirm the ten largest assets and inventory movements. Renew owner certifications annually.
Adversarial review
Does the universe include off-balance-sheet property; is every owner proven; do inventories use the correct averages and raw-material value; is FX correct; do fixed assets apply months and floor; do exclusions meet conditions; is partial use authorized; are other activities separated; do serials reconcile; does DIEMSE use the same base?
Every answer should point to a document and computation.
Minimum deliverable
Asset master, certifications, ownership maps, inventory averages, fixed-asset workpaper, FX, leases, authorizations, physical/customs/accounting reconciliation, exceptions, review and bridge to the 6.9% result.
Monthly inventory protocol
Set a common cutoff for opening and closing balances. The foreign principal, Anexo 24 and warehouse may close at different times or time zones. Document received-not-recorded, in-transit, quarantine, consigned, repair and third-party inventory. Prevent double counting between locations.
Reconcile units before value. Code every difference as timing, unit of measure, BOM, scrap, return, standard-cost adjustment, owner or error. A value adjustment should not conceal a quantity difference. Close monthly and carry an open-item list.
Compare turnover and obsolescence. If the owner writes inventory down, determine which value Article 182 recognizes at import and document the policy. Do not copy a reserve without analyzing the rule.
Test work in process and finished goods by rebuilding raw material from bills of material and consumption. Remove local conversion only through a verifiable computation rather than a global percentage. For complex products sample families and reconcile to total.
Special asset events
For a new line record acquisition, entry, installation, testing and in-service date. Presence during installation may differ from productive use; document facts and position. Apply the statutory monthly treatment for midyear acquisitions rather than an improvised average.
For relocation identify departure and arrival dates, customs records and benefiting plant. Prevent two maquiladoras from including the same asset for the full year. For sequential shared use allocate periods with evidence.
For disposal retain approval, sale, destruction or return and physical removal. A zero-value asset still available may remain relevant. For a casualty document date, insurance, replacement and control.
Mergers and principal changes require chain of title and data continuity. Do not restart cost or date without support.
Year-over-year bridge
Prepare a roll-forward: prior base + additions + inventory + FX + value changes − disposals = current base, by owner. Explain major changes through volume, investment, currency and method. Compare the 6.9% result and dominant test.
A decline in foreign assets with stable production may signal missing data or a transfer. An increase without capital expenditure may reflect FX or inventory. Ratio analysis directs testing.
Keep criteria consistent. Where a method changes, quantify the effect and document whether law, system or error correction caused it. Do not reclassify to obtain a lower result.
Foreign-principal certification
The certification should be signed by a knowledgeable owner and assert completeness, values, currency, title, dates and use. Attach schedules by entity and contact. Mexico should validate rather than merely archive.
Set preliminary monthly, annual-close and correction deadlines. If the principal uses another fiscal year, define an extraction for Mexico’s period. Reconcile additions and disposals after the first file.
Where an old invoice is unavailable, document alternative evidence, limitation and position. Escalate material unsupported assets before filing.
Directed sampling
Cover the highest-value items, all exceptions, every owner and a random sample. For each test existence, title, cost, date, currency, use, customs record and computation. Log findings and extrapolation where appropriate.
For inventory select peak and closing months, new products and negative balances. Recalculate the average and conversion. A December-only sample does not validate twelve monthly averages.
The reviewer should rebuild Result A from schedules without editing the master. Protect formulas and link evidence.
Responsibility matrix
Foreign fixed-assets supplies acquisition and owner data; foreign inventory supplies values; Mexican warehouse controls quantities; customs controls entries and returns; plant confirms use; accounting supplies local assets; tax applies methods; internal audit tests. Name a person and backup for every function.
Define escalation for late data. An unavailable foreign register cannot be solved by using Mexican book value without analysis. Estimate for monitoring, but replace with certified values before filing and preserve changes.
Meet after every quarter to close owner conflicts and high-value differences. Minutes should state decisions and evidence, not only attendance.
Sources and cutoff
This article was verified as of August 2, 2026. Consult the current Mexican Income Tax Law, particularly Articles 181 and 182, the SAT Safe Harbor notice page and the OECD Mexico profile. Confirm annual rules, authorizations and exchange rates.
Zugzwang delivers an Asset Base Review combining ownership, use, averages, valuation, FX and reconciliation to support the 6.9% result.