This article analyses the impact of market forces and regulation in the Spanish telephone sector. It aims to explore the combined effects of the intersection between regulation of the monopoly, economic policy and entrepreneurial strategies, and hypothesizes that the regulation had a decisive influence on the development of the networks and services. Chronologically, the study covers the two decades of the transition from autarky to the Stabilization and Development Plans. In its double supply-demand approach, the article quantifies investment as an expression of supply and reviews the ground rules within which these two market forces developed. Finally, it examines the situation of shortages that the intervention created, and explains the intervention in prices from the perspective of the trade-off between its use as an element of stabilization and the bargaining power of the sector. The conclusions reflect the impact of the regulation and highlight its more complex aspects.
