The story
The PSI-20 was initiated on 31 December 1992 with a base value of 3,000 index points. The index experienced considerably more volatility than the world's main financial markets between 1998 and 2000, caused by uncertainty in the world's emerging markets: a sharp increase of over 50% in the PSI-20's value in the first four months of 1998 was followed by a decline of similar magnitude between July and October of that year. Another price surge sparked at the tail end of 1999 peaked with the index's highest value to date, 14,822,59 set on 3 March 2000. The Portuguese blue-chip market's subsequent performance has broadly followed the trends set by other Western indices, falling in the aftermath of the dot-com bubble before recovering significantly from 2003 onwards.
From Wikipedia’s article on PSI-20, shared under CC BY-SA 4.0.3
