Stock market indexes are the instrument which financial markets use to track and analyse how share prices are moving on the stock market over a given period of time. They act as a thermometer, monitoring the health of the market�s star performers. In the case of the IBEX-35, this reference is a selection of the 35 most representative shares trading on the Madrid Stock Market.

The IBEX-35 is an open list which is updated twice a year to ensure that the companies chosen really are the market�s front runners. This index lists only the top 35 companies by market cap on the Spanish Stock Market, and only admits a new entrant when this order changes, and a previously ranked company is excluded. The decision as to which shares should enter or leave this prestigious ranking is taken by a Committee of Experts, based on objective valuation criteria. There may also be movements in the IBEX-35 if two of its companies merge, thus leaving the way clear for a new candidate to join the index.

As in the Dow Jones index, there are four subdivisions within the  IBEX-35. They are: Financial Ibex; Industrial and Others Ibex; and Utilities Ibex.
Being on the IBEX-35 is a way for some of the most powerful listed companies in Spain to establish their credentials, such is the economic and financial importance of being included on the index. Generally speaking the rest of the listed companies tend to follow the movements of the IBEX-35 companies on the market.

The select shares of the IBEX-35, are in alphabetical order :Acciona, Aceralia, Acerinox, Acesa, ACS, Altadis, Amadeus, Bankinter, BBVA, Banco Popular, SCH, Carrefour, Corporaci�n Financiera Alba, Endesa, FCC, Gamesa, Gas Natural, Grupo Dragados, Grupo Ferrovial, Iberdrola, Inditex, Indra Sistemas, NH Hoteles, Prisa, Red El�ctrica, Repsol YPF, Sogecable, Sol Meli�, Telef�nica, Telef�nica M�viles, Telepizza, Terra Networks, TPI-P�ginas Amarillas, Uni�n Fenosa and Zeltia.

The IBEX-35 was created on December 28 1989, with a value then of 3,000 points, compared to the current 8,300 points. Among its foreign counterparts are the French CAC 40, the British FTSE, the German GDAX, the Italian MIB 30, the Belgian BEL 20, the Dutch AEX, the Brazilian Bovespa, the Swiss Market Index, the Portuguese PSI, the Mexican IPC, the Chilean IPSA and the Japanese Nikkei. The Dow Jones index was founded in 1884 (105 years before the IBEX-35), with just 11 shares listed. It is the most famous stock market index in the world and is made up of the 65 shares with the highest market capitalisation currently trading on the New York Stock Exchange.
Other interesting indexes are the Smith-Barney (S&B) which lists the top 100 growth shares, and the Nasdaq 100, which lists the world�s main tech company shares.