Fil: Garay, Mauricio Ezequiel. University of San Andrés. Department of Economics; Argentina. “This work estimates the market power of the firms involved in the retail marketing of naphtha in Argentina in 2017. To this end, the demand curve is estimated through the application of the Berry Logit Model (1994) and the Random Coefficient Model Berry, Levinsohn and Pakes (1995), the latter not previously applied to any market in the country. The results show a significant and stable dominance over the rest of the players over the YPF state flag over the rest of the players, among whom no significant dispersion was found. Analysis of cross-elasticities reveals that YPF’s preponderance manifests itself against each of the other flags and shows that there are no punctual rivalries between flags.”