The IBEX 35 is the benchmark stock market index of Spain, representing the 35 most liquid and capitalized companies listed on the Madrid Stock Exchange. It serves as a key indicator of the performance of the Spanish economy and is widely followed by investors. The index is calculated using a free-float market capitalization methodology, meaning that only shares available for trading are considered. The IBEX 35 includes major companies from various sectors, such as finance, telecommunications, and energy, making it a diverse representation of the Spanish market.