A recent study by Portugal’s Energy Services Regulatory Authority (ERSE) has found no evidence of fuel operators profiting from rising prices. The study, covering the period from January to July 2026, indicates that fuel prices are primarily influenced by international market quotations rather than crude oil prices directly. This challenges the common perception that prices increase rapidly but decrease slowly, a phenomenon often referred to as the ‘Rockets and Feathers’ effect.
The ERSE report also highlights that while diesel prices may initially drop less sharply than they rise, this discrepancy is not statistically significant after a few weeks. This finding is crucial as it counters widespread beliefs about fuel pricing practices, suggesting that operators are not exploiting market conditions to inflate their margins.
Additionally, the study addresses the price differences between Portugal and Spain, attributing them largely to taxation rather than operator pricing strategies. Without taxes, fuel prices in Spain would actually be higher than in Portugal, indicating that tax policy plays a significant role in consumer costs.
As fuel prices are projected to rise again next week, with diesel expected to increase by 10 cents per litre, the implications of this study are significant for consumers. Understanding the factors behind fuel pricing can help drivers make informed decisions and potentially mitigate the impact of rising costs on their household budgets.
Source: Euronews

