Most of the firms who have set up maquiladora factories have been American firms coming to capitalize on Mexico's cheap labor. There are currently more than 2000 such factories in Mexico. They are mostly located along the US border, with a "twin-city" relationship--factory in Mexico, management and sales in the US-- established with the neighboring US city.
因為廉價勞工而到墨西哥設 Maquiladora 的，多是美國企業，所以墨西哥現有的這兩千多家「加工保稅出口廠」，大多集中在美墨邊境，並與對面的美國城市，結合成工商一體發展的雙子城。