Transmissão assimétrica de preços: o caso do mercado de gasolina por atacado e varejo no Brasil

Abstract

This study analyzes the asymmetric price transmission in Brazilian gasoline markets, discussing a different approach considering the national publications before, as the non aggregated analysis into the cities, retail gasoline price adjustments ratio in (gas stations) due to wholesale prices variation (supplier) and the wholesale gasoline price adjustments ratio comparing the municipalities given the price makers. Among the suggested hypotheses as major determinants of those asymmetries are the adjustment cost and non-competitive markets existence. This work aims to analyze retail and wholesale gas prices dynamics in Brazil under a regional approach, using weekly database for 134 municipalities, between May 2004 and February 2011 period. Cointegration approach for threshold adjustments and momentum threshold error corrections (TAR) and (MTAR) were used. The main conclusion for retail industry is cointegration statistical evidence between retail and wholesale price series in 103 municipalities and 96 by the TAR and MTAR models respectively. For retail asymmetries, TAR Error Correction Model and MTAR Error Correction Model approaches pointed to symmetrical price adjustments in 70 municipalities. In terms of spatial distribution on retail results, southeast and south had a higher proportion of municipalities with symmetrical transmission prices. This result is similar to the North and Midwest regions. However, there was a reversal aspect in northeast region. Cities presented asymmetry considering other regions. Considering wholesale market, 115 municipalities cointegrated by ECM TAR and ECM MTAR approach with the price makers municipalities. Results suggest a higher level of integration between these markets for the gasoline wholesale prices. By price dynamics analysis, asymmetry evidences are stronger with a 45% proportion (52 municipalities) introducing asymmetric relationship by ECM TAR approach and 27% (32 municipalities) by ECM TAR approach. Both retail and wholesale results suggest a low efficiency by price transmission process. Cointegration results also suggest a common long-term relationship between prices in retail or wholesale levels. This relation by asymmetry results is not settled efficiently. There are differences in price adjustments to different shocks (positive and negative). Thus, no gas stations transfers efficiently prices to consumers considering market changes and by last, nor the wholesale market transfers to peripheral municipalities gas stations those existing prices in big markets near the suppliers.