Spanish stock market indices reflect the economic performance of companies listed on the Bolsa de Madrid, Spain's main stock exchange. Launched in 1992, the IBEX 35 is the flagship index of the Spanish financial centre. It includes 35 of the most liquid and capitalised companies listed on the Bolsa de Madrid and is used as the main indicator of Spain's economic and stock market health. It is revised twice a year to select companies that are representative of the Spanish economy and have a sufficiently high market capitalisation and liquidity. This major index covers various sectors, including banking, telecommunications, construction, energy and retail. In addition to the IBEX 35, the IBEX Medium Cap and IBEX Small Cap list mid-cap and small-cap companies respectively. These Spanish indices are used by investors to monitor market performance, compare the performance of certain active management strategies (benchmark), but also and above all, for the creation of financial derivatives such as futures and options offering hedging, arbitrage and investment opportunities. These Spanish stock market indices are also used as benchmarks for index funds and ETFs designed to offer good portfolio diversification at low cost. The Comisión Nacional del Mercado de Valores (CNMV) is the Spanish authority responsible for guaranteeing fair trading and protecting investors.