Historically, each economic zone (geographically) has its own index. So, for example, in the euro area it's EURO STOXX 50. The ESTX50 includes 50 of the most liquid shares in the euro area. The composition of the index is subject to an annual review each September. The index is available in the most popular world currencies: EUR, USD, CAD, GBP, JPY. ESTX50 includes simultaneously 12 leading European countries. The index is updated online traditionally every 15 seconds throughout the day from 9 am to 6 pm CET. This condition is relevant only for EUR and USD, while the calculation of other currencies is made only at the end of the working day.