In order for a foreign company to operate as a maquiladora in Mexico, first, a legal entity needs to be established. Once established, the IMMEX and VAT certificates need to be requested to the Mexican government. This could take time and money. As an alternative to start enjoying the benefits of lower-cost manufacturing in Mexico without having to establish a legal entity, the Mexican government allowed the shelter companies, under the IMMEX program.

A shelter company is a legal entity established in Mexico that assumes all risks and liabilities and produces manufacturing services to a foreign entity. The shelter company (it could also be a foreign entity that owns the Mexican legal entity) and the foreign legal entity that wants to manufacture in Mexico usually require a legal agreement.

The shelter company normally provides HR, procurement, accounting, taxes, safety, import/export and compliance services for the manufacturing operation. The foreign company normally owns any assets required for the manufacturing, the raw materials, and the finished product as well as the manufacturing know-how and is accountable for the quality and product and any related liabilities.