The CNMC has published resolutions that establish the relationships of principal and dominant operators in the energy sector based on data for the year 2024. This is in accordance with the Real Decreto-Ley 6/2000, which mandates annual determinations of these operators.

A principal operator is defined as one holding one of the five largest market shares in a given sector. The regulations impose limitations on individuals or entities that hold a significant stake in multiple principal operators within the same market, requiring them to notify the CNMC of their voting rights and administrative appointments.

Dominant operators, defined as those with a market share exceeding 10%, must comply with specific obligations related to market mechanisms and representation in the electricity market. The CNMC's resolutions detail the dominant operators across various sectors, including electricity, natural gas, fuels, and liquefied petroleum gases.

For the electricity sector, the dominant operators include Naturgy, Endesa, and Repsol, while the gas sector lists Naturgy and Endesa among others. The resolutions aim to ensure compliance and promote fair competition within the energy market.