It is the main index of the Spanish stock market, and is used as the underlying index for various derivative products. It is composed of the 35 most representative securities of the continuous market, i.e. the companies that have the highest trading liquidity, volume and frequency. The Ibex 35 family has a series of sectoral indices: the New Market, Utilities, Financial, Industry and the Other and Complementary Ibex index. The group of listed companies that constitutes the Ibex 35 is reviewed every six months, to ensure that this index always consists of the most liquid securities on the stock market.