PSI 20 index
What is the PSI 20?
A stock index that's linked to the Euronext Lisbon Stock Exchange in Portugal.
The Portuguese Stock Index 20, to give it its full name, is made up of the 20 companies with the largest market capitalisation and share turnover on the exchange.
Where have you heard about the PSI 20?
Investors often pay close attention to the movements of the PSI 20 when reviewing the performance of the wider Portuguese economy. The index was formed in December 1992, with a base value of 3,000.
What you need to know about the PSI 20.
The PSI 20 is a free-float, capitalisation weighted index. Its membership is reviewed on an annual basis by the PSI Steering Committee, to ensure the index remains accurate. It was previously reviewed twice a year, but this was changed to improve stability.
The PSI 20 faced notable turbulence between 1998 and 2000, on the back of uncertainty in the world's emerging markets. It faced further volatility after the dotcom bubble burst, but has recovered significantly since 2003.