The CAC 40 is a benchmark French stock market index. The index represents a capitalization-weighted measure of the 40 most significant values among the 100 highest market caps on the Paris Bourse (now Euronext Paris). It is one of the main national indices of the pan-European stock exchange group Euronext alongside Brussels’ BEL20, Lisbon’s PSI-20 and Amsterdam’s AEX.
The CAC 40 takes its name from the Paris Bourse’s early automation system Cotation Assistée en Continu (Continuous Assisted Quotation). Its base value of 1,000 was set on 31 December 1987, equivalent to a market capitalisation of 370,437,433,957.70 French francs. In common with many major world stock markets, its all-time high to date (6922.33 points) was reached at the peak of the dot-com bubble in September 2000. In 1 December 2003, the index’s weighting system switched from being dependent on total market capitalisation to free float market cap only, in line with other leading indices.