This paper analyses the economic and social impact of a State aid programme designed to incentivize the development of the border provinces of the Dominican Republic. The intervention method chosen was based on tax exemptions, creating a possible tension between the objective of territorial cohesion and that of upholding market competition. In the competition sphere, the study analyses whether the law had the effect of increasing the market power of beneficiary companies. In the social sphere, it establishes a criterion of regional similarity and compares the evolution of the border provinces with that of other similar provinces. These procedures yield an overall measure of the impact of the initiative. In addition to assessing this particular case, the article contributes to the design of a methodological approach for the economic and social analysis of regional interventions.