Price-Volume Relationship in Polish Stock Market

A relationship between daily prices of Polish WIG index and trading volumes is investigated. By introducing variables related to a number of last prices and volumes, a history of values in a certain period of time (which could be regarded as an investor memory) is taken into account. Different characteristics of autocorrelations for prices and trading volumes are observed. By studying mutual correlations between the variables, a local maximum at about 100 trading days is discovered. The Granger causality test is performed, indicating very strong influence of prices on volumes. This property can be considered as a sign of markets maturity.