In both the automotive and the electronics industries, the small size of the protected plants constrained the generation of backward linkages. Throughout the country’s IS period, upstream auto parts suppliers in Mexico were concentrated in simple operations where scale economies were small (e.g., springs, coils, and stamped plastic articles) and not in operations requiring larger production runs to be efficient (e.g., catalytic converters, fuel injection assemblies, or exhaust systems) (Peres Nuñez 1990). Computer component companies in Mexico resorted to hand sol- dering of connections rather than automated assembly techniques. To meet domestic content requirements, Hewlett-Packard and Compaq had to settle for local purchases of fiberglass housings for their computers, because the operations of Mexican suppliers were not large enough to support the use of advanced plastics and composites.