The CAC 5 and the CAC 40 take their name from theParis Bourse's early automation systemCotation Assistée en Continu (Continuous Assisted Quotation). CAC 5, inaugurated on 23 June 1986, was a version of the Toronto Computer Assisted Trading System, the first fully automated trading system.[2] CAC 5 consisted of Leroy-Somer, LVMH, Synthélabo, Eurocom and UCB.[3] CAC 40's base value of 1,000 was set on 31 December 1987, equivalent to a market capitalisation of 370,437,433,957.70French francs.[4] On 1 December 2003, the index's weighting system switched from being dependent on total market capitalisation tofree float market cap only, in line with other leading indices.[5]
The CAC 40 index composition is reviewed quarterly by an independent Index Steering Committee (French:Conseil Scientifique).[4] If any changes are made, they areeffected a minimum of two weeks after the review meeting.[4] At each review date, the companies listed on Euronext Paris are ranked according tofree floatmarket capitalisation andshare turnover over the prior 12 months.[6] From the top 100 companies in this ranking, forty are chosen to enter the CAC 40 such that it is "a relevant benchmark forportfolio management" and "a suitable underlying asset forderivatives products".[6] If a company has more than one class of shares traded on the exchange, only the most actively traded of these will be accepted into the index (generally this will be the ordinary share).[6]
The CAC 40 is acapitalization-weighted index. The number of shares issued (used to calculate the market cap and hence the index weight) of a company is reviewed quarterly, on the third Friday of March, June, September and December.[4] Since December 2003, the index weightings of companies in the index have been capped at 15% at each quarterly index review,[6] but these range freely withshare price subsequently. A capping factor is used to limit the weights to 15% (if necessary), and is reviewed annually by the Index Steering Committee on the third Friday of September.[6]
The index value I of the CAC 40 index is calculated using the following formula:[6]witht the day of calculation;N the number of constituent shares in the index (usually 40);Qi,t the number of shares of companyi on dayt;Fi,t the free float factor of sharei;fi,t the capping factor of sharei (exactly 1 for all companies not subject to the 15% cap);Ci,t the price of sharei on dayt;Qi,0 the number of shares of companyi on the index base date;Ci,0 the price of equityi on the index base date; andKt the "adjustment coefficient for base capitalization" on dayt (reflecting the switch from the French franc to theEuro in 1999).
Although the CAC 40 is almost exclusively composed of French-domiciled companies, about 45% of its listed shares are owned by foreign investors, more than any other main European index.[8] German, Japanese, American and British investors are amongst the most significant holders of CAC 40 shares. This large percentage is due to the fact that CAC 40 companies are more international, ormultinational, than any other European market. CAC 40 companies conduct over two-thirds of their business and employ over two-thirds of theirworkforce outside France.[9]