Laspeyres index

Price index that tracks the performance of a historical portfolio over time.

The Laspeyres index is used to calculate the value of a portfolio, whose composition was established at a given base date, in terms of the prices in effect at the reporting date. The composition of the portfolio thus does not change over time. The stock indices of Deutsche Börse – DAX® , MDAX® , etc., are calculated using the Laspeyres formula. Because the historical portfolio would become obsolete with time (e.g., when new companies are included in the index, or when companies in the index file for bankruptcy), Deutsche Börse adjusts the formula to account for the new portfolio at each review date.

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