Shipping consigned tooling, molds, and machinery to Mexico under IMMEX: AF, F5, and ownership protection

In almost every nearshoring project, the U.S. buyer eventually ships capital equipment south of the border: a USD 250,000 injection mold, a progressive stamping die, a custom end-of-line test rack, or a CNC cell. Usually there is no sale: the U.S. company retains legal title and lends the equipment to the Mexican contract manufacturer (or its own subsidiary) to produce parts.

This is where two different worlds collide. To the U.S. buyer, the mold is “our property sitting on the supplier’s floor.” To Mexican customs (SAT / ANAM), that mold is temporarily imported foreign merchandise under customs control, tied by law to the Mexican plant’s IMMEX program and its AF pedimento.

If the documentation, physical serial-number plates, bailment contract (comodato), and Anexo 24 Fixed Asset module are not aligned before the truck crosses at Laredo or Otay Mesa, two risks appear later:

1. During a plant audit, SAT inspectors can initiate a precautionary seizure (PAMA) on the machine if the physical data plate does not match the pedimento.
2. When you want to pull your tooling out of a struggling supplier and move it to a new factory, you discover you cannot legally move or export the mold without the first supplier’s customs cooperation.

Editorial note. General operational guidance only; not legal, tax, or customs advice. Fixed-asset temporary imports are governed by Article 4, Section III of the IMMEX Decree, the Customs Law (Ley Aduanera), and Anexo 22 / Anexo 24 of the RGCE. Always structure bailment agreements and customs entries with Mexican legal counsel and a licensed customs broker. Independent resource operated by Heberey LLC.

1. Use the right pedimento code: AF (not IN)

Under Article 4, Section III of the IMMEX Decree and Apéndice 2 of Anexo 22, capital goods: machinery, equipment, tools, instruments, molds, and durable containers: enter under pedimento code AF (Activo Fijo).

Never let a shipping clerk or broker lump a mold, fixture, or spare machine onto a standard raw-material declaration under code IN:

• IN is for inputs that rotate: they enter, get consumed via a Bill of Materials (BOM), and leave inside a finished product within 18 months (or less).
• AF is for assets that stay and produce: they are not consumed by a BOM. Under the IMMEX Decree, AF goods remain authorized for the duration of the IMMEX program’s validity (subject to the specific rules of the decree and any applicable IVA/IEPS credit deadlines under Anexo 30 / 31).

2. The physical data plate trap (Brand, Model, and Serial Number: NS)

Mexican customs law places strict identification requirements on machinery and equipment. When customs officers conduct a physical inspection at the border (reconocimiento aduanero) or a factory audit (visita domiciliaria), they walk up to the machine and compare its physical manufacturer data plate against the Partida and NS (Número de Serie) identifier on the AF pedimento:

3. Accounting books vs. the Anexo 24 Fixed Asset module

In our Spanish-language compliance reviews, one of the most frequent blind spots inside Mexican plants is the gap between financial accounting and Anexo 24:

• If the Mexican plant bought the machine, it sits on the accounting balance sheet for depreciation, and finance assumes “it’s recorded.”
• If the U.S. buyer consigned the mold at zero purchase cost, it does not sit on the Mexican plant’s balance sheet as an owned asset: so nobody in accounting tracks it at all.

In both cases, if the equipment entered Mexico temporarily under code AF, it must live inside the Fixed Asset module (Módulo de Activo Fijo) of Anexo 24. That module tracks the AF pedimento number, item line, tariff code, description, serial number, physical location, and eventual discharge (RT return, V1 virtual transfer, or F5 change of regime).

4. Protecting US buyer title: the Contrato de Comodato (Bailment Agreement)

When you consign equipment to a third-party Mexican contract manufacturer, the AF pedimento is filed under the Mexican supplier’s RFC and IMMEX number: because the Mexican supplier is the Importer of Record.

To prove that the U.S. buyer: not the Mexican factory: owns the tooling (and to support the customs valuation method declared on the COVE and Manifestación de Valor when there is no sale), you need a bilingual Bailment Agreement (Contrato de Comodato) executed before shipment:

• Explicit schedule of assets: Attach an exhibit listing every mold or machine with the exact description, brand, model, serial number, and replacement value that will appear on the AF pedimento.
• Physical ownership plaque: Require the supplier to keep a visible plaque on the tool stating “Property of [U.S. Company Name]: Imported temporarily under Comodato.”
• Unconditional obligation to execute RT or V1 on termination: Include a contractual covenant (backed by remedies) obligating the supplier and its customs broker to sign and validate the return (RT) or virtual transfer (V1) pedimento within a fixed number of days when your commercial relationship ends.

5. Closing the loop: RT, V1, or F5

Temporary fixed assets cannot simply be retired to a back corner of the warehouse when a product model goes end-of-life. Every AF line item remains an open customs liability until it is formally closed by one of four actions:

1. Physical return abroad (RT): Exporting the mold or machine back to the U.S. (matching the exact serial number from the original AF pedimento).
2. Virtual transfer (V1): Transferring the tool to another IMMEX factory in Mexico via mirror V1 pedimentos so production can continue at a new supplier.
3. Change of regime to definitive (F5): Paying the applicable import duties and 16% VAT so the equipment becomes permanently nationalized in Mexico.
4. Authorized destruction: Following the formal SAT destruction notice and witness procedure under the RGCE when an obsolete tool or die is scrapped in Mexico.